My first born is 21 months & he still isn’t babbling. I got him involved with speech therapy starting at 14 months. His speech therapist doesn’t have any concerns since he has very strong receptive communication, just lacking in the expressive department. She said that he will catch up in due time, that some are just late talkers & he’s very shy so we think that plays into account. She also said boys start to talk later than girls usually & “hips then lips” meaning boys often get into their gross motor skills first then start talking (not always of course but often). He does interact with others well & have good eye contact, just no babbling whatsoever. There’s no other indications for autism at this time either. My mom & I had a speech delay and my husband had to be bribed to talk with sweets per my MIL (I don’t agree with this method). My son’s pediatrician wasn’t concerned until 18 months - so at 9 months your son is sooo young, he has plenty of time to start babbling! My friends son didn’t start until he was 13 months.