E.H.
If you are sure it is because she is trying to find a place for her teeth while nursing and NOT biting, then you could try adjusting her position. My son did this when he got his front teeth, and what I did was when he was latching on, I pushed him into me so he had a deeper latch. I also tilted his head a little until it was more comfortable for me. It was kind of like at the beginning when he was trying to figure out how nursing works. With new teeth, everything changes and they have to figure out how to nurse with teeth in the way without hurting mom or without interfering with nursing. You could also try a different hold (football, side-lying, etc), although at 9 months, your daughter may have a favorite position that she won't give up. Hope this gives you some ideas. Good luck!