19 month old sleeps 9.5 hours a night?

He goes to bed 8/8.30 but wakes at 5.30/6. If we put him to bed earlier he often gets up earlier. Once he wakes in the morning, he won't resettle and if we try to leave him - going in every 10 mins to say it's still bedtime - he gets distraught and the neighbours get annoyed. He sleeps for 1.5 hrs in the day anytime after 1130 because we battle to keep him up until then, he's a bit cranky and yawning at points of the morning. I wake him after 1.5 hours because he used to sometimes sleep for 3 hours, and we found it ate into is night time sleep (previously around 10.5 or 11 on a good day) but now he's on 1.5 nap and 9.5 at night. What's the best solution? Live with it or make a change? Any constructive tips or advice would be much appreciated. Thanks!