Hey Lisa,
Maybe he doesn't need as much sleep as other kids. I know some kids don't sleep as much. When my oldest was old enough (probably around 3.5 and it depends on the age and maturity.), I would tell him if he wakes up and everybody is still asleep, he could play quietly in his room. I'll leave him some crayons and paper and some books or quiet toys.

I put both boys to sleep around 8:30-9:00 and they wake up at 7:00 or maybe even a bit earlier. The big one plays quietly in his room if we are not awake. He's 5 now so he's better at it. At the beginning, we'll have to tell him but now he's used to it and plays quietly in his room until everyone wakes up which is not long anyways.

You could always put him to bed later and see if he would sleep in. But it'll take a few days to see if that method works because he'll need to be adjusted to the new schedule. Good luck!