ZwiDomini

I spent some time in foster/group homes too, although in my late teens.

For me, the thing I responded best to (and still respond best to) was kindness. The wariness you are seeing might be them watching for some indication that the hammer is about to drop. And it could even be for really "stupid" things. Kids who have been through abusive situations might have been punished in some way for truly trivial mistakes, or things that weren't even mistakes at all (when sane people look at the same situation). It instills a certain wariness of how things are going to be responded to by others, even if what they just did was totally normal or innocent. The topic of foster homes might trigger that reflex, even if they largely have learned that regular people don't do those sorts of things.

Everyday kindness, and letting things go without being remarked on even if they're slightly odd, goes a long way.

Is your book only available on Amazon?

I like to buy books off of Barnes & Noble (or, any site other than Amazon) when possible, mostly as a small way to keep competition against Amazon alive.