My DS is a little older than yours but has been in the same sort of pattern since he was about 14 months or so.
It doesn't matter to him what time he sleeps. He can sleep until 5pm and still be ready for bed at 7.30pm. We don't sit with him, just give him his bath, brush his teeth, read a story etc and then put him to bed somewhere between 7.30pm and 8pm, usually more like 8pm if he woke up at 5pm, although this is rare.
When he was about 12 months old we'd wait until he actually fell asleep before putting him to bed as he was fully breastfed at the time and would fall asleep on the boob. We decided to break this cycle at around 13 months or so and bit the bullet.
We'd put him to bed after the bedtime story, give him cuddles etc and close the door. We'd then leave the room.
We had to go back upstairs ooh, at least 30 times or so that first week because he'd stand at the top of the stairs throwing down teddies to get our attention. One of us would pick him up, give him a kiss and say "no, sleep time now" and put him back to bed.
After a week or so he got the hang of it, and now when he goes to bed he stays there. I sometimes hear him talking to his soft toys until around 8pm, but he is happy enough and it has really sorted out his sleep patterns. He now wakes up at 7am, which is far better than the disturbed patters we had previously.
He really needs his naptime and we use a similar process during the afternoon. I never wake him up though, but appreciate some people might have to because of school runs etc.