hi there
when you say he can only manage 2hrs A time are you going by his cues? At his age short naps can mean undertiredness. If you want to try to extend his A times you can do it really gradually, say 5-10 mins every few days until he gets used to it. Keep stimulation really low key, maybe at the time you would normally start your winddown, perhaps sit with him and read a book for 5-10 mins then carry on with winddown as normal.
Also have you tried to extend his naps? THere are many techniques you can try to help him sleep longer.
I think he is fighting that 2pm nap because he is not tired enough. If he can go from 9.15am till 12noon on 1.25hrs sleep, then if he has a 45min nap at 12- 12.45, he can probably last until 2.45-3pm before needing another nap. I know with dd if I ever tried to put her down before she was sleepy she would go nuts and fight it no end and end up not falling asleep at all, even when it got to her normal nap time, as she had gotten so wound up. Maybe this is what's happening? Try putting him down a little later and see if it helps.