Hi there & welcome
!!!
I would make the following suggestions:
* make bedtime much earlier. Start with 6.30pm to give him the chance to catch up on some sleep. He should really be doing at least 10.5-11hrs at night & at the moment he's only getting 9 hrs at night so he's probably very overtired.
* don't offer the morning nap any earlier than 9-9.30am
* wake him up 45mins into the morning nap & offer the afternoon nap about 3.5hrs later
* let him have 1.5hrs in the pm
* make bedtime 3.5-4hrs from the pm nap
So... your day would look something like this:
wakes (be it 5.30am)
9:30-10:15 - morning nap
1:45-3:15 - afternoon nap
6:45-7pm - bedtime
this is all related to transitioning to 1 nap. ALot of babies are capable of doing this nice long morning nap but then it affects their morning wake up time. So by waking him up from the morning nap earlier, he should add those hours onto night sleep & his afternoon nap will hopefully increase at the same time. Might take about a week to see how you are going but in the meantime I would definitely bump up the bedtime because he should be getting more sleep at night. 99.9% of the time, a later bedtime leads to earlier wakings.
hth
Layla