A.R.
I know this will sound backwards, but have you tried putting him to bed earlier? Many times an early wake time is a sign the child is over tired. Even if you just move it back by 20 min it may make a difference. When my kids miss their bed time (7pm) by even 15 min they are up much earlier without fail. Also, sometimes they wake up earlier at this age because they are becoming more social. I would try not going to him until 6am. If you just let him fuss for a while he might go back to sleep and he will also realize their is no gain from waking up so early. It is really hard at this age. I would try earlier bed time first. My 9 month old goes to bed at 6:30 and sleeps until 6:30. It sounds early, I know, but at this age it seems their circadian rhythm is set to an early time. Good luck!
A.