2nd time moms!! Help!

So my boyfriend has a 9 month old. He sleeps in his crib but literally wakes up every hour or so. He is teething but it was worse a couple of weekends ago. We will pick him up to comfort him and he's instantly calm. I know he wants to be held by us but he needs to sleep in his crib.. We give them baths before they go to sleep.. Play some lullabies and even make sure he's full before he goes to bed. I'm up every few hours and it's so exhausting. He used to sleep so good :(