Your husband shouldn't feel like getting professional help is going to make the dog perfect. Trainers are there to show you and teach you what to do, but raising the dog truly is up to the owners.
Instead of doing private lessons why not find a place that does group sessions? In group sessions the instructor will talk and show you how to practice things, and then give all the students some practice time in class while he/she observes to make sure you do everything correctly. Trainers really are just there to coach you guys
Definitely get some sort of professional help. I don't think that private lessons are necessarily a must since your pup is only 9 weeks old. Privates usually are for the pups with issues. If your puppy ever shows resentment towards your children for example, that would be a good reason to get private in home help.