I have a 9-week pup. A local trainer said he would start protection work at 3 1/2 months. Should I do this?

It would be much better advice to spend a little money and purchase 2 videos from me: Puppy Bite Work and The First Steps of Bite Training. The reason for this is that all the initial work in protection work should be done through prey drive, (you can read about this in the article section of my web site). There are too many people out there that claim to be professional trainers that in fact are not. You as the handler need to learn about prey and defense. You can get a foundation in this work from my videos. Once you do this, you will be able to evaluate a dog trainer to at least know if he understands the drives of this work. These tapes will provide you with enough information to do the first 10 to 12 months of work yourself. Then you can go to someone else for help if your dog is ready for it at that time. Some dogs can't go to a different helper until later when they mature more.