
Hi Joanna
I would advise you to avoid castration if at all possible - in some cases (although not all) it can make the coat very woolly and hard to manage. Obviously if there's a medical reason or a real temperament problem as he grows on, you may need to consider this, but if not I would say no.
At 9 months he is no doubt 'feeling his feet', as most males will. I would suggest that you just keep on top of him, make sure he knows you're in charge and let him know kindly but firmly what is and is not acceptable behaviour.
Nervous of loud noises - well, he's a Collie, and they can be great wusses :D - don't make a fuss of him to 'comfort' him through it, act as normal and if anything keep the noise level up a bit - bang around at home etc.
Why don't you join the board so you can post any other specific questions and join the chat - there are many knowledgeable people on here, in all breeds and specifically in Collies.
Marina