I think DS was about the same age when he started being a PITA to get to sleep. I'd try forcing the boob into him, when he clearly didn't want it & was wide awake. It drove me nuts!
He never went down that early, usually between 8 & 9, but some nights then were as late as 11... even later if I let DH deal with it while I went to bed!
I thought it was just because he realised he was going to sleep & that sleep is boring. He's only just starting to get a bit easier & earlier in the last few weeks, but thats at the price of his day sleep! He did have one today....coz he was up at 5, after crashing at 7 last night!