See I wouldn't
. I would work on the Mr Sun bit and drop back to a 7.30pm bedtime. My reasoning would be that there is no point losing your Evening time over something that isn't fixing.
I also wouldn't be prepared to do very late bedtimes on a kid that had just started full time school as being exhausted could make it harder for them to settle properly.
My DS would have been exactly the same at this age I'm afraid, I really do think some are genuinely wired to the early am, and what you have to teach is not interrupting everyone else in the process.
My DS came in at 5.50am yesterday and 6.15am today as well. He goes back and stays quietly after that but I've never managed to stop him coming in completely. Yesterday he wanted to tell me he needed the toilet. I guess he is checking I am there and he is safe
.