J.R.
First question: She probably is getting enough. If she weren't, she would be fussing for it. Because she is eating so much solids, she probably doesn't need as much milk. Also, at 8 1/2 months, she's probably pretty good and efficient at nursing and doesn't need the long sessions anymore. Don't worry.
Second question: She may be biting because she is teething. Have you tried any teething remedies to ease her discomfort? Otherwise, I would recommend that you just keep unlatching her when she bites. Hopefully she'll learn to associate biting with no more nursing and stop.