This Halacha is an excerpt from our Sefer
May a child eat or drink before Kiddush?
If a child wants or needs to eat or drink, he may do so even before Kiddush. This applies both to the Kiddush of night and day. It is forbidden to oppress a child and make him wait until after Kiddush. This applies even if the child is above the age of Chinuch/education [so long as he is under Bar or Bas Mitzvah]. If, however, the child does not want to eat and does not need to eat at this time, and is simply being fed for the benefit of others, then [once he reaches the age of Chinuch] he is to be educated not to eat until he hears Kiddush. Nevertheless, it is permitted to give a child who has reached the age of Chinuch to drink from the Kiddush wine in Shul. [Despite the above ruling, as the child becomes older, one may encourage the child to not eat before Kiddush by stating to him that it is proper for him to abstain on his own from eating or drinking until after Kiddush, even though if he needs or wants to eat, one may not stop him from doing so.]
It is permitted for a child to eat or drink before Kiddush until the age of Bar/Bas Mitzvah, if they desire to eat. It is forbidden to oppress the child by making him wait. Nonetheless, one may encourage the child as he gets older to not eat or drink before Kiddush, even though he may do so from the letter of the law.
May children eat candies before Kiddush?
Yes. This applies even if the child has reached the age of Chinuch, until the child is Bar or Bas Mitzvah. Nevertheless, as stated above, it is proper to encourage the child, as the child becomes older, that it is proper for him to refrain on his own from eating candies until after Kiddush. Nonetheless, if the child needs or wants to eat, one may not stop him from doing so.
 Admur 269:3 regarding Kiddush in Shul; 343:7; 106:3 regarding eating prior to Shacharis; 471:10; 472:23; M”A 106:3; 269:1; M”B 269:1“It is permitted to feed children food on Shabbos morning prior to Kiddush and it is forbidden to oppress him”
Other rulings of Admur: In 343:6 Admur states “Even though the child can wait to hear Kiddush in the place of a meal, in the house of his father who is educating him in this” which implies that ideally a father should educate his child to not eat before Kiddush. Perhaps however this is referring to if the child does not feel a need or will to eat or drink before Kiddush, in which case one would then educate the child to wait. Alternatively, perhaps the father may encourage the child not to eat until Kiddush, and only to force the child not to eat is forbidden.
 Wording of Admur in 343:7
 So is the wording of Admur in 343:7; 471:10, and Ketzos Hashulchan 147:5 that the allowance only applies if the child needs to eat; See last footnote below.
 Admur 269:3
 Admur 269:3; 343:7; M”B ibid “It is forbidden to oppress him”
The reason: As the [Sages] only prohibited feeding [Rabbinically] forbidden foods [to a child] when the food is forbidden in it of itself, such as a piece of Treifa [Niveila] and the like. However, if the food is Kosher in it of itself and it is just forbidden to be eaten within a certain time slot, then it is permitted to be fed to a child. A proof for this is the ruling regarding feeding a child on Yom Kippur in which case one may do so even if there is no danger involved for the child to fast. [Admur 269:3; M”A 269:1; Yevamos 114b]
 SSH”K 52:18; Piskeiy Teshuvos 343:1; According to this, those who are accustomed to make their older children [over 9] delay eating until they hear Kiddush, not only are doing a matter that is unnecessary but it is even forbidden to do so as stated above.
 Such as if an adult asks the child to eat a food for the sake of tasting it to see if it needs spices and the like.
 See M”B 269:1 that this is approximately between ages 6-7
 Based on Admur in 343:6-7; 471:10; Ketzos Hashulchan 147:5 that the allowance only applies if the child wants or needs to eat, and so is clearly implied from 343:6 which bases the allowance of giving a child to drink from the Shuls Kiddush on the lenient opinion mentioned there [and not on the differentiation between a timely and innate prohibition]. Furthermore, in 343:6 Admur states “Even though the child can wait to hear Kiddush in the place of a meal, in the house of his father which is educating him in this” which implies that ideally a father should educate his child to not eat before Kiddush. Seemingly this is referring to if the child does not feel a need to eat or drink before Kiddush in which case one would then educate the child to wait. So is also the implication of Admur 621:4 who forbids giving a child to drink the wine of a Bris on Yom Kippur, even though a child may be fed on Yom Kippur, thus implying that there is a difference between whether something is done for his own need [feeding him] or for the need of others [giving him the Bris wine].
Ruling of Admur in 269:3: In 269:3 [as well as 106:3] no mention is made that it is only allowed if the child wants or needs it, and on the contrary, it is implied from there that even if the child feels no desire to eat he may nevertheless be fed, as the case there is discussing giving a child wine of Kiddush from Shul. Thus, seemingly there is no prohibition at all by such foods even if the child does not need or want to eat. However, perhaps one can answer that the reason why no mention of “need/want” was made in 269:3 is specifically because the case there was referring to giving the child to drink from the Shuls Kiddush, of which in truth there is no need for him to want to drink it, as since it is being done for the sake of a Mitzvah and it is a mere time prohibition, it is allowed according to all. The ramification between the two approaches would be if a parent may feed a child before Kiddush even if the sole purpose of doing so is that the child tastes the food on one’s behalf.
 Admur 269:3; 343:6; Michaber 269:1; Hagahos Maimanis; Tur; See Kaf Hachaim 269:2 regarding the allowance of giving a child to drink the Kiddush in Shul and the various Answers offered
Background: When making Kiddush in Shul, usually there is no one being Yotzei with the Kiddush, being that they plan to eat at home and make Kiddush again there. Thus, the question is asked as to how one may make Kiddush in Shul if no one is being Yotzei. To this, the Alter Rebbe answers that although an adult may not drink the wine, since he must eat in the place that he made Kiddush, nevertheless, a child who has reached the age of Chinuch may drink from it, after hearing the blessing from the adult and fulfilling his obligation.
The reason: We find in Admur two different [and contradictory] reasons behind the allowance: 1) As children may be fed Kosher foods which are time forbidden. [269:3] 2) Alternatively, although the child does not need to drink this wine [and it should hence be forbidden despite the fact that it is only a time forbidden food], nevertheless, it is permitted to give it to him being that it is for the sake of making Kiddush, and is not done on a steady basis, and is only Rabbinically forbidden. [343:6] See previous footnote! See Kaf Hachaim 269:2 for various reasons mentioned in Poskim
 See Admur 343:6 “Even though the child can wait to hear Kiddush in the place of a meal, in the house of his father which is educating him in this.” One must establish that this refers to the father encouraging the child not to eat until Kiddush, as to force the child not to eat is forbidden as stated above, and thus from here we can conclude that one may educate the child through encouragement [Perhaps however this is referring to educating the child not to eat in a case that he does not feel a need or will to eat or drink before Kiddush and is being given to eat for other purposes-Vetzaruch Iyun]; See also Admur 343:7 “Therefore it is permitted to feed him before Kiddush if he wants to eat” which implies the child does not have to be educated to eat if he does not want to; So also rules: Or Letziyon 2:47-6; Piskeiy Teshuvos 269:2; See Likkutei Dibburim, vol. 4, p. 1418 that Rabbi Yosef Yitzchak of Lubavitch related: When I was seven years old, my father [Rabbi Shalom Dov Ber of Lubavitch] said to me on the eve of Yom Kippur: “In the evening and all night it is forbidden for you to eat. Tomorrow in the morning until noon you do not need to eat. From then on it depends on your will.” My father explained to me the gravity of eating on Yom Kippur, and concluded: “If you want to eat, do not ask anybody, only come to me. I have prepared food, water, and juice for you. If I am in the middle of the Amida prayer, wait for me; just be careful not to ask for food from anyone else.” That year I completed the fast for the first time in my life, and the year after that it was already an easy matter.
 Or Letziyon 2:47-6; Piskeiy Teshuvos 269:2