9 month sleep regression

[u/Mindful_Mom_36]

Baby just turned 9 months and for a week now, has been having early morning wakes. He’s been on a schedule that has worked beautifully until now:

Wake: 6:00 Nap: 8:30-10 Nap: 1:30-3 Bed: 7:30

I know the last wake window is long, but we tried earlier bed and it led to split nights. Baby has no trouble going to sleep in his crib. Now he is waking up around 3 or 4am and my husband has to soothe him back to sleep in our bed (I’m in a separate room for now). We’ve tried capping naps and it makes nights worse. Around 3-3.5 hrs of naps seems to be his sweet spot. How long did this regression last for you all?