Wow, this is a tricky one. But since you are asking out of love, it should be OK to ask the questions.

First, I would talk to your husband. He should be behind you 100% or you should not do it. It wil be painful for him, I expect.

I would think that the kid would be all for it since you are his mom as far as he is concerned, the one who cares for him, and who he loves, etc. However, once you have talked to your husband, approach it with a "I love you so much, and would like to make our relationship official. I am in no way trying to say that your mom did not exist or that you shouldn't love her, but I am here to stay and wanted to know if you would like me to adopt you." A 9 year-old child should be able to handle this type of question. My 10 year-old (who has a bio-dad who is not very involved) approached us with this request a couple of years ago (asked me if my husband would adopt him), so I think at 9, your stepson should be able to deal with at least a discussion on it.

The tricky part is that it will stir up some painful emotions since the mother did not choose to leave. Play it by ear, I am sure since you love him you will do what is best for him.

Good luck.

Saili