C.S.
My 9 year old son just started going to bed at 9:30. The last couple years have been 9. There really is no set in stone time. I guage his time by how he gets up in the morning. During the summer and baseball season, we will move his bedtime up, especially if he has a baseball game, or if he looks super tired. But, both my kids are sleepers. My two year old didn't want to get out of bed this morning...haha. People think I am kidding when I tell them that my kids sleep in until 9 or 9:30 on the weekends...haha
It is really up to you to use your mom guage. I put my kids to bed early in the summer and later in the winter. Just watch them. They will tell you what the right bedtime is.