9-10 months is a really classic and normal time to have sleep problems. Its a difficult time in their lives- learning to crawl (and practising in sleep!), the start of separation anxiety, really getting into solids, teething. There is heaps happening for them and it is really common to have sleep difficulties at this time. I have lots of sympathy!

My only advice is do what you need to get through it, and it will eventually pass. You can try not to create too many bad habits, but don't beat yourself up about doing what you need to in order to get him to sleep. If you need to feed to sleep or rock or lie down with your bubs, then do it. Once the difficult time is passed you can break those habits.

You are not alone! I put up a very similar post around this time and found out sooooo many others had gone through the same thing.