I do the same thing with my dogs....up in the early morning and than back to bed for four more hours. Wheather they come back to my bedroom or out roaming the house. I rarely have a problem with them needing to go back out or making any messes. They always wait until I get up.
Try making his last meal of the night earlier/with no late night snacks. Be sure that he has had a potty break as late into the evening as possible. Than make his first potty break in the morning earlyier as well. Making sure to leave him out long enough to potty (pee & poo). If you leave him out for 5-10 min make it 10-15. Should do the job.. 