This is not a battle I'm willing to fight (too hard) by the time they're teens. I do try to get them up and going by 9. I'm a morning person, so to me, the morning is half-gone at 9, but others in my family don't see it that way. 
With my oldest, we tried for 9 or 9:30. My dd is extremely motivated and self-driven, but she's a night person who needs a long time to wake up. So I cut her some slack. She always gets the work done. My current 15yo is in school and is experiencing the joy of catching the bus at 6:50 a.m.
If they're mature enough (not all are), they can regulate themselves and get the work done no matter what time they start. I think it's different with every child. I still have to tell my 15yo when to go to bed every single night.
"Ree-bee," Mom to former United States Marine ds and math teacher DIL * artist dd 20 * motion-loving ds 17 * piano-playing ds 12
"For Miss Minnie loved children and she loved books, and she taught merely by introducing the one to the other." from "A Consent," by Wendell Berry