Hello! I don't know why but I just can't get this sleep thing right with my kids and I try so hard. I'm looking for advice or reassurance that this is ok?

My son is a terrible terrible sleeper. Although last month he started to sleep though the night but he would sleep 6-4. I've been working on making his bedtime later, in the hopes he will shift his sleep. For the past 3 week he will sleep 7:30-4:30 or 8:00-5:15. I don't get him out of his crib until 5:30 but he has only once put himself back to sleep. He puts himself to sleep at bedtime and all through the night. He seems happy but 9 hours of night sleep just isn't enough, right?

Any suggestions?