It sounds like she's not ready, and I'd really be hesitant about leaving my dd/ds with someone who was not honest about what went on while I was gone. I mean, what else are they going to hide from me, you know?
Your baby is still an infant. Let her nurse to sleep. Believe me, there will be a time when she will fall asleep on her own.
ETA: The Baby Whisperer advocates schedules and isn't conducive to a healthy breastfeeding relationship. Toss that right out the window. Have you read any Dr. Sears books?
In my opinion, you don't. There is NEVER a reason to hit a baby. A nine month old's job is to explore and learn, and the grown up's job is to make sure he/she is safe by providing a safe environment. Have you tried some redirection/distraction? Is your baby's environment babyproofed and safe for exploration? Can you put things up/away?
What do you mean by violent?