My bf broke up with me, 9 months later he apologized for being a jerk and asked to be friends. I said sure and we've been talking and I think I'm developing feelings for him again. What should I do?

It might be good news and worth looking into it. You need to know if he, too, has any romantic feelings for you. It is as simple as asking him if he does. If he does not, then you have a choice accepting his friendship or, if you cannot have him as just. a good friend, see if you would not be better off without him in your circle. If he says he does have romantic feelings, you should have a heart-to-heart talk about the circumstances of your break-up and see what can be done better for the two of you.