My step-daughter's school library is open until 5pm and she goes there every day after school to do her homework. Do other schools not offer this?
And as bizarre as this might sound, outside of New York City, unaccompanied children on public transportation is basically not a thing in America. We assume the children are lost / abandoned and the parents are delinquent / trying to get the kid kidnapped by a pedo.
There was a decently widespread news story a few years ago about someone calling the police on a mother because she let her kids go to the park by themselves.