I agree with Joanna, you are the mother so therefore discipline must be handled by you always, any other way and you risk the chance of damaging any potential relationship your daughter will have with your husband.
Have you discussed with your daughter the new changes that are taking place? If not, now would be a great time.
Also, try to re-inforce the wonderful and new changes that he will add to both of your lives. Remember though, it all pretty much depends on you, you must lay the ground work but also let her know that no matter what, you will always be there for her and he is not replacing her.
Also, let her come to him on her own terms, just encourage him not to respond negatively, be open, responsive and receptive, don't give up and stay positive. Try doing things together; this always helps to break the ice. Try doing things that she loves to do.
This is a big change for her and although children are resillient, changes to the overall structure of their family is really big for them and if you don't handle this well, she will remember this as a sore spot for many years to come. She may even grow up to resent him and you. So don't act in haste, handle this gingerly. So what if she doesn't share your enthusiasm right now, it is to be expected, she is only 9. This is all new for her.
Besides, If he is as great as you say, she will come around. It will take some time but she eventually will. Just don't force her let her do it on her own terms, she'll see how happy you are and will be happy that someone is making her mom happy.
So good luck to you and your daughter and many blessings to your new family.