I can't access the OHSAA website right now, but I believe they are OK, using a loophole in the bylaws by calling this kid as a student manager. I see nothing wrong if this kid is being used to help out if needed in practice, to shag balls or step in as a runner while the coach is explaining a defensive situation. If this kid is actually practicing right alongside the HS kids throughout the entire practice, that might be pushing it.
I'll continue to research, and find some solid info.