As a parent to the child, can you allow the child to use your details to pass KYC verification, if asked? And if you do that, does it also mean that you are supporting underage gambling?
No - in fact from the start I would not allow him to gamble or try to gamble, so that kind of case will not happen. I don't want to be another person who allows their underage children to gamble instead of preventing it. Underage gambling is prohibited and should not be done under any circumstances - but perhaps some parents might consent to KYC documents if there's a large win waiting to be withdrawn.
I am not trying to make you look bad, but if turns that your child has won a million, I think you would change your mind and give him your details for KYC verification. I think everyone would do so. Speaking for myself - I would give my data to pass KYC and withdraw a big win. But, if that success was achieved without me knowing about it (gambled secretly) then I would get really angry and figure out a punishment. Probably I would hold that big win until child turns 18+. I think that would be fair.