My kids all did things like that. My 8 year can still be found on our floor in the morning when he has had a bad dream in the middle of the night. he seldom wakes us up but does come in and makes himself a pallet and falls asleep.
I would tell him that he can no longer sleep in our room unless he takes a nap. PERIOD. That waking up that early is ok if he doesn't get grumpy, but he gets grumpy so he has to choose. take a nap and sleep in our room on the floor, or not take a nap and sleep in his own room. No compromise. If he takes a nap tell him to go to the floor or to his room, it doesn't matter, but he has to choose. So let him.
But if chooses your floor know that he will grow out of it. There was a time when all 3 of my sons were camped out in our room for various reasons. Even though they have their own rooms and beds. We just went with the flow. they are required to pick up pillows and blankets in the morning as I don't like them all over the floor all day. But i let them comfort themselves by sleeping near us. Not in the bed with us, but in the room with us. I wouldn't worry to much, he will grow out of it. All of mine did, and now we only have the occassional interloper.
good luck,
L.