I can only speak to where I went to school, but even now, 90% of kids ride the bus. I'm not sure how school can start at 10:00 if the parents have to be there to get an 8 year old safely on the bus but somehow still make it to work by even 9:00.
It is teens who due to changes they undergo during adolescence that would greatly benefit from much later school starts, and they should also be old enough to be able to get to the bus without parents supervising them.
Elementary school is fine with its current schedule because all the students there are pre-adolescent, so the parents could still deal with getting an 8 year old to the bus.
Middle school is in the middle so might not have a good answer. It will likely have many students who have started adolescence and would do better with a late start but are not yet independent enough to be able to handle getting ready and getting to the bus without their parents still around. So probably need to keep early starts for middle school.
