I've started teaching my 8 year old how to shoot. Basic 22 rifle (Crickett), and it turns out he is cross master eyed (Left eye dominant, right handed). I tried some of the uisual tricks to see how bad it was, but ended up having him shoot left-handed. He just couldn't get a sight picture with both eyes open, which might be a function of the standard peep sight on the rifle.

When trining adults in this situation I've been successful in getting them traind using their dominant handedness. Any sugfgestions for working with children?

My daughter is the same
She has to shoot her bow lefthanded but can shoot her AR right handed with a red dot.

Conventional wisdom via NRA Instructors Guide is teach him to shoot left handed.  Some people can learn to shoot cross dominant but not many.  As young as he is I would say he's better off learning to shoot as a lefty.

I was left eye dominent, but was able to teach myself to switch to my right. My istuctor has taped shooting glasses and used eye patches to train eye dominency. It works, but takes time.