If DS wakes at 5am should I cut his morning nap?

[kbaby]

Ds has started waking up at 5am. Hes wide awake and no amount of cuddling him in bed works. Hell stay in his cot for 20mins or so but then yells to come out.
The problem is hes so tired by 9am that he sleeps until 11am, then has another 1hr nap at 4pm ish.
He goes to bed 8pm and wakes once at night for milk.
Hes 10 months

So should I wake him after 45 mins in the morning and get him to have a longer nap after dinner or wont it make any difference.

i've also got an early riser but i'm convinced its the sun being up so early - yersterday morning it was a 4.30 start!!! Thankfully i ordered those easyblinds a few days ago so i've put them together - OMG - i think you could develop photos in his room its that dark! Pray for me that it works(i'm going loony with all these early starts)!!!