Grew up in Ohio in the 80's same deal from 6th through 11th grade. Hour long bus ride, class started at 7am. Nice thing was we were the first off the bus on the way home, so we were home by ~3pm and got to sleep for a couple hours before parents came home.

Another benefit of delaying start is fewer kids driving in the dark in winter and more time for morning fog to burn off on those marginal days that weren't bad enough in town for a delay.