A.B.
If your boyfriend has asked for your hand in marriage or is even hinting at a long-term, permanent commitment, then it would be wise to meet your daughter with you having explained that this is a serious relationship and he might become a permanent fixture. Then, hopefully, you'd plan a decent engagement period to give her time to get used to the new arrangement and new person in her life. If this has been going on for 9 months, but neither or you are sure where it's going, then it's too soon to bring him into the "family" picture. It would only confuse her if later the two of you decide to call it quits, and then not only would you have to grieve the relationship, so would she.