K.J.
At 9 months, babies are more aware that they are by themselves. It is a version of separation anxiety that many babies, including my 15 month old, suffer around that age. My daughter would also cry so hard she would throw up and I didn't like that. I continued to nurse her to sleep (or if it was someone else they gave her a bottle while they held her, never in the crib) until she fell asleep. Then I would put her in her crib after she fell asleep. I didn't start putting her in her crib awake until she was 14 months.
I know many mothers and doctors say you should teach them to fall asleep on their own, but that just didn't work for me or my child. I firmly believe in motherly instincts, so if you don't feel comfortable letting him cry it out, then don't and don't let other people pressure you. You are his mother and know what is best for him. Trust your instincts!! You are doing a great job!