They kick pretty good. It's light compared most all turkey guns, but not compared to a deer rifle. My six year old didn't mind it until he missed a turkey with it. He was five when that happened. Now he'll tell anyone who will listen it is the worst gun in the world. I got him a youth Yildiz 20. He'll shoot it and does fine. The recoil isn't any less and it's harder for him to hold up, but its not associated with that time he picked his head up and missed a turkey.
The .410 TSS loads are as light as it gets, regardless of gauge. You can either put the same type load in a heavier gun or add weight to the .410. You could add weight to the butt where it is easier to hold and still have the lightest possible weight out from the shooter, where it is most difficult to hold. The tricky part with a young shooter is whether you get a huntable pattern without choking it. The SumToy turkey choke is tight as necessary to get what we adults would want. It throws a small pattern.