got a 9 1/2 month DS, almost identical to yours until a few weeks ago.
Can't guarantee any of this will work for you but this is what we did...
The first thing we did is that i stopped breastfeeding him when he woke in the night, he just had water when he woke for a couple of weeks, and DP went into his room to give him this instead of me. This taught DS that if he woke up early, he would not get mommy or her milk. The health visitor had told me that by this age they should not need to feed during the night, and if you refuse to feed them at night you will see a sudden increase in the amount of solids that they will eat, which will mean they soon stop waking in the night, especially if they know they aren't going to get the milk they are used to! (FYI DS actually lost weight between mid June and mid July, when i was still feeding in the night, so all of these changes we did have happened since mid July, and since then he has gone from 20lb 5oz to 22lb 2oz today!)
We then did about a week of DP trying to give him as little water as possible, then giving him no water and just rocking him to sleep. We combined this with making sure that when it was an acceptable time to wake up, we would go into his room, open the curtain/raise the black out blind, say wakey wakey and then go to his cot. When putting him to sleep, we'd say sleepy time, close blind/curtain. We decided that he was allowed to have his breakfast (weetabix) from 6am, but not before. We hoped that he would soon learn there is no point waking any earlier as he won't get milk, or water, or breakfast.
It may seem harsh but we didn't get many tears over it. It's been a couple of weeks now, and gradually he started to wake a bit later, then we had a breakthrough when he woke one day at 5, but then self settled rather than the usual screaming, and then woke again at 7.30, the next day woke at 5, self settled then woke 7, the next day woke at 6, the next woke at 6.30 and the next woke at 6.20.
this may still sound early, but it's way better than waking anytime from 4am, and DP has to be up just after 6 anyhow to get ready for work, which means i'm always awake too, so whilst it'd be nice if DS slept in for longer, it fits in with us if after 6 so not complaining!
We also removed the winnie the pooh dreamshow from his room.
hope this helps!