I think there are two pieces to this puzzle and it would be good to attempt to look at them separately if possible.
1. how much sleep does he actually need? On one hand - he's not tired, doesn't seem irritable, etc. On the other hand - what happens on days when you don't wake him? If he sleeps another hour or two when you don't wake him then that might hint that he's not getting enough (and is somehow good at not being a grump about it).
2. possible difficulty falling asleep/winding down. Some people take a while to fall asleep, some people need a consistent routine, no screen time, exercise earlier in the day (but not right before bed), etc or they take a long time at night. If moving his bedtime later *still* requires an hour then maybe there are some skills/routines that could be learned to shorten it, or maybe his hour of pondering life is what works for him....
FWIW my DS11 goes to bed at 9:00/9:15 and gets up at 5:30/6:00 and has consistently for the last year or two. We have no need for alarm clocks in our house
