We had the same prob with Ryan not long after he turned two. Firstly we cut his day nap out which worked a treat (in bed by 6pm) but after a while he was not having a daynap and still up at 9pm and not acting tired or ready to go to bed.
In the end it was that tiring having him up all day without a break and then going to bed the same time as us we enforced bedtime. It was a battle at first but our new rule was that it was bedtime at 7pm and he could choose if he read books or played but he was to stay in his room. After a few nights (and many tantrums for those first few nights of being put to bed at 7pm) he was going to bed at 7pm and out like a light within 5mins. I think he was tired all along but getting a second wind to keep him up till 9pm. Now he sleeps 7pm-7am with no day nap. He is 3 in a few weeks. Our second Jayden is a brilliant sleeper but only cause we've learnt so much from our experiences with Ryan and not allowed the same bad habits to creep in. Jayden sleeps 7pm-6am without a peep and then has a two hr nap during the day. He is like one of those little dolls that you put him in his bed and his eyes close to go to sleep LOL cause we have kept his sleep to a stricter routine than we did with Ryan.
I don't know if doing what I suggested will work but just thought I'd share our experience for food for thought.