An interesting option would be to allow junior-high kids to play high school sports if they fit the age requirements. This would enable them to get four years of eligibility regardless of what their personal circumstances are.
I think that runs into the issue of how many are hoping to go to college on athletic scholarships. A year away from competition makes it hard to be recruited and would put someone far behind competition wise. I know academics are the primary concern, but there are a lot of people who mostly do what they have to in the classroom to get to play.
When I went to junior high there were students too old to play in high school. Since they couldn’t make the grades to the next level, they were stuck in junior high until they gave up and dropped out.