baby still not sleeping 9 months old

My son is 9 months old and is still not sleeping during the night.Since birth he has not been the best at sleeping partly I think due to myself always picking him up so he is used to contact all the time and is quite petted and clingy.I breastfed until 7 months old during this time he slept in my bed and about a month ago I finally got him to sleep in his cot.Some nights when I put him down he falls straight asleep but others I have to rock him for ages and he will appear to be asleep but as soon as I put him down he screams.I try and leave him to cry but can't do so for long.When he eventually falls asleep he's awake within four hours.I give him a bottle and he either falls straight back asleep or again fusses,its as if he cannot get comfortable and can sometimes be like this for an hour and a half,bearing in mind this happens a good 5 times a night.Before bed I give him a bottle so I don't understand why he keeps waking up so much Is it just because he is used to this I wonder.My friends have babies the same age and I cannot believe their babies sleep all throughout the night without waking up I am amazed lol.Does anyone else have problems with their babies sleeping?