i think your friend has some wise advice for you. You should throw the bottle away, at nine years of age your child is completely able to deal with the loss of this comfort.

there are many kinds of fun drinking cups out there, character cups, shaped cups etc try to introduce this kind of replacement. You will have to be firm and strong about the continous use of a bottle. I would think about sending him to school with it and tell the teachers that this is what he is to drink from in front of all his friends, maybe hummiliation is the answer. Throwing the bottle away is also a great learning tool he can use later in life, since this is not the most disturbing challenge he is ever going to endure! As for the nightie thing, you can buy him silky pyjamas for boys or make them yourself ( ask someone to make for you).