My son was doing this and the earliest I put him to bed was 6. Now he naps every 2/3 days and it's works out fine now. Bed at 6.30 every night and wakes at 6.30. You should try him napping every few days and should help.
Managed to keep him up till 5:55, so he should sleep in till at least 6AM.
I miss nap time, pregnant with DC2 and not sure how I will cope not being able to catch up a little during the day!
Oh well, I should be grateful he napped till 2.5, I try to get him to nap on some days but he's just not interested anymore - just sits up in his bed and plays, ill keep trying though, never know your luck!