9歳個胸平係正常. Normally when the time you start your puberty, you will have "m" period, 通常女仔黎M後,個胸先慢慢發育 it about the age of 10-18, some people start earlier or some start pretty late . You are absolutely normal, do not worry.
Yes, it's normal according to my knowledge and experience. Puberty for girls starts from around eleven years old. So, you don't have to be worried. You will experience it anyway.
It's abnormal to have puberty so early!! The end!!