Introducing new puppy to other dog at home

Any tips for what we can do so they can both relax at home better?

We just brought home a 9 week old boy puppy and we already have a 14 month old girl dog. Our dog has been with us a year, and then my husband decides to pull the trigger on a new pup to be her playmate… it has been two days since we’ve brought him home and they are doing OK, I think? She constantly wants to play with him but he will correct her and needs time to relax too. But when we put him in the playpen or separate him he seeks her out and whines for her… a couple of times they have played a little rough and he will whimper and cry and we separate them immediately.

I fear he might become reactive or something from her constant pawing him and playing too hard when he doesn’t want it. I also fear she might become too anxious because this new puppy is constantly moving about in her home and she doesn’t relax unless he’s in another room sleeping.