Info we share and are open with that some people believe is not age-appropriate: world religions and beliefs of others, death and afterlife-not just our personal beliefs, reproduction & birth, homosexuality-frieds had two mommies, and he wanted to know why, so I told him the truth., divorce, disabilities, homelessness, charity, ghosts and supernatural (he's very interested in this), and the aging process.
Info we limit exposure to and discourage: excessive junk food, killing of any kind-we don't even encourage killing bugs, death of children (because he worries about his own death), bad language-the big ones and others including words like "hate, shut up, stupid, dumb, idiot, darn", child abuse, potty humor-ok, my husband's not too good at reinforcing this one!, TV shows that have no positive benefit at all, video games r/t killing or violence, violence in general. I think these are typical for most of us.
Wow you sound a lot like my husband and I

Unfortunately we don't homeschool right now and so far I haven't had much trouble with him picking things up at school. He went to a small private school last year and this year he's at a small public Montessori school. He's very impressionable though and I do worry about this in the future.