Sorry to read your news about bites; facts is Westies are Terriers and moast Terriers bite. Being very active and "intense" dogs thay get wound up and sometimes bite. I have seen it many times and it's one of the reasons some people give up their dogs for adoption; they think they got a cuddly puppy and they end up with a dog that bite: big shock!
Westies have a strong personality and they like to show it, they must be loved for what they areL small dogs with a BIG dog atitude.
Personally I think your problems can be controled avoiding wound up situations now that he is still young. Dont raise your voice in this situations, just take the dog away from the place and talk to the dog in a calm voice. If you have a crate never crate him as a punishment, the crate should be his place of safety not a place of punishment.
Don't let the situations escalate, as you see he is getting too excited take him away from the situation and talk to him in a reasuring voice. Give him the idea it's nothing special and we shouldn't waste our time with neighbour's dogs or childreen playing.