Sounds like he is getting a great night's sleep - what a joy.
Probably he just does not need as much sleep as you would like for him to get during the day. You can try to put him down a little later in the mornings and then a little later in the afternoon so that perhaps he won't be too exhausted by 8pm OR you could put him to bed earlier. Depending on his cycle, it does not necessarily mean he will get up earlier.
I always tried to go with my children's natural body rhythm rather than what was convenient for me.
My son was not a good sleeper and had reflux badly. My daughter had more spitting but her reflux did not hurt like my son's and she was a solid sleeper. As an infant she slept for 10-12 hours and took 3 naps. But as she became more active, she held onto the night sleep and slept less during the day. However, if she did not get in the bed by 6:00-6:30 her whole day would be ruined. Keeping her up later made her sleep less. We realized the best thing for her was to forgo a social life for a few months of our lives and so one of us was always at home by 6:00 putting her to bed. It was not easy, but it did not last forever. Both my children 4 and 6 years old go to bed by 7:30pm at the latest on school nights. My son gets up by 5-6am regardless of what time you put him to bed so putting him to bed later just makes him cranky during the day. As hard as it seems, you have to figure out what works best for as you can see from reading these posts - different families find different ways of dealing with the sleep issue. The most important thing is that your baby gets enough sleep, and you get enough. Blessings!