(unsolicited male perspective)
|So far we haven't left him to babysit for her while I am out.
He's her dad, not a babysitter, right? anyway .....
I digress ..
He should suck it up and spend some 1:1 time with her.
We were cosleeping for the first couple months, but as is the way of things in my rather unusual circumstance my partner and I aren't sleeping in the same bed ourselves, so my son sleeps with mom and I get the lonely bed.
Every night though I spend several hours with him usually alone just the two of us. Sure he gets upset some days and I have to hold him and rock him and soothe him. Sometimes I'll put on the baby carrier and walk around if he's being really fussy. If it seems like he is tired I might put him in the stroller and push him around the block (my version of driving around the block, I prefer to leave the car in the garage and get some air).
Most of the time though we have fun! Probably a unique and different experience for him: dad time vs mom time. I read to him, sing and play musical/rhythmic games and such. We do a lot of silly things that make both of us giggle. He's a great kid and I'm honored to share these early months of his life with him.
My partner cosleeps, and I haven't slept with either of them in months but my son will fall asleep in my arms, especially fall asleep if I'm wearing him, likes to cuddle with me when he's in a cuddly mood and I can tell he loves me. You daughter loves her daddy too, she's very young and they have to just learn to interact together in a way that makes them both happy and content. I truly do not believe that co-sleeping is the issue in your situation, but rather one of comfort. Mostly the comfort your husband has with his child. The only way to work on that is to throw the two of them together and let them work it out.
Nine weeks is still very young but I think the right approach is not to have them avoid each other. He does need to figure it out. If he just puts her in a crib (not an option for me, we don't own one) then he's not trying enough but if he really wants to expand their bond, extend a little trust and leave the two of them together for an hour (make sure she's fed first). Then make it two. Don't go far and be on call but let them work it out, and I think it will work out. Good luck to all three of you :-)