Hi Justin, just so you know, the training I am doing with my female at this time, is for sport. IPO is a sport, the protection routine is very patterned. Bad IPO training could make a dog aggressive, and so could bad personal protection training ( as you call attack training). I am NOT experienced with personal protection training, BUT, from what I understand, they train the dogs to protect in real life scenarios, if done incorrectly this could make your dog aggressive, could make him start to see potential threats everywhere you turn... 9 months is not too old, imo he is too young for any type of work with pressure. I don't see anything wrong with doing personal protection training, as long as you understand you are teaching your dog to bite in certain real life scenarios, so you NEED to train with someone who has a lot of experience, and understands the CC breed or even the mastiff breeds.