As a parent I will say that a menu that is easily read by the tin lid will be more effective in engaging the interest.
Many parents take every opportunity to allow their kids to read and make their own decisions on such matters so I would suggest adult phrasing for adult dishes and child phrasing for children.
As a regular visitor to assorted restaurants with WMPG since she was too small to eat chicken, I am sure that when chicken appears on a children's menu it is always chicken without bones.
No restaurant with any intelligence is going to serve children's portions with bones unless this is very clear on the menu - for example chicken legs, chicken wings.
So, if it is a children's dish, I think grilled chicken should be sufficient. You might add in small print (may contain bone) but as LRV suggests, most parents will check anyway as they cut up the chicken.
I'm no chef but doesn't "deboned" mean that the bones have been removed? If this is for a menu, "deboned" is properly not appropriate but in the context of Bernar3's question, couldn't you say "grilled, deboned chicken"?
Boned is one of those strange words that seems to mean the same as the word you expect to be its opposite, deboned.
Boned chicken has no bones.
Deboned chicken has no bones.
Boned underwear has bones.
Debone does not appear in the OED, but of course the prefix de- is there.