Bed time is completely irrelevant unless one includes wake up time. The thing we have always stressed in our house is whether or not you are getting enough sleep.
Our twin boys (13, in 8th grade) go to bed around 10, though if one of them is tired, he will go to bed earlier. They have to get up around 6:30 on Wednesdays, for chamber orchestra at 7:15; Monday and Friday they have to get up at 7, for orchestra at 7:45. Tuesdays and Thursdays they don't have to be at school until 8:30, but they get up at about the same time on those days. I think it's very important to keep a pretty consistent schedule all week.
My sons usually stay up a little later on weekends, but not a lot, and they don't usually sleep too late on weekend mornings.
At one point they argued about 10 bed time, and I explained that if they consistently got up before the alarm, that would show that they were getting enough sleep, and could stay up later. Since they usually need to be awakened in the morning, they understand that they need all the sleep they're getting.
They stay up later - and sleep later - in the summer, when they don't have a schedule.