I've had similar early wake ups with my 6 month old. Sometimes as early as 5.30.
I changed a few things a couple of weeks ago, although I did them altogether so not sure which one it was that helped!
I started to feed his last feed at 7pm, I also weighed him and checked that he was getting the right quantity as they grow all the time. He did need more.
I moved his crate where he could see my other Cocker.
I made sure he didn't get too much rest in the evening.
And I've been able to, through the school holidays, vary the time we get up so that he doesn't have our usual alarm time stuck in his mind.
Something has helped because he is happy until 7.15/7.30 now.
Last wee at 10.30pm - a proper empty with a stroll around the block.
He gets plenty of stimulation through the day also.
Good luck, I know from experience it can be very tiring.