A.V.
I would break the latch and tell her no. Then take a short break. At almost 9 mo, she will be alright with an interrupted nursing session. You might also tell her "gentle, gentle" when you go to nurse her. My DD had to be reminded when she got new teeth. It seemed to change her latch a little. It can be changed and she can be taught that biting = no nursing. Also, try nursing her longer when she's sleepy and watch for signs that she's full/goofing around and end the session before she gets bored.
I didn't put DD on the floor, but I did set her on the couch away from me and didn't continue to hold her in a nursing position. I didn't want her to start to think that biting would get her playtime.
It worked out. DD nursed til she was 2.5.