I am a big fan of crate training. Both my dogs are kennel trained and go to it the moment they see us putting on our shoes (unless we ask them if they'd like a ride in the car).
Is it necessary? No, not really, providing your dog isn't destructive (mine knock over the garbage can every time we go out if left out of their kennels). I just find it makes them much easier to train, and now and then they'll just go there for a nap. They like to have their own quiet place.
Edit: I have a problem with the responses that say 'If you work that many hours you shouldn't have a dog'. The fact of life is that MOST people work full 40 hour work weeks, and since dogs are the top pet in North America, I would wager to guess working 40 hours a week and being apart from your dog isn't a bad thing. It doesn't make the dog 'bad' in any way. I agree that on the night you have school, you should probably get a neighbour to bring your dog outside for a walk. But having your dog at home alone for 8 - 9 hours is not going to harm it. You should consider an older dog, though, rather than a puppy. Puppies shouldn't be left alone for more than 5 or 6 hours at a time, and ideally no more than 3 without a bathroom break.
Amazing that people think leaving a dog alone for 8 - 9 hours is a big deal, but yet when it comes to our children, we'll stick them in daycare for others to raise, yet complain when they're being 'bad'.
In any case, I would be very careful about the choice of dog. Since you aren't going to be home all the time with your new little one, choose a dog that suits your lifestyle. Low-energy dogs, or dogs that aren't prone to destructive behaviours when they don't have the opportunity to go outside for extended periods of time, are a better choice for you. You should avoid any of the hunting and working dogs and probably choose a toy breed. Toy breeds, while not requiring extensive time outside, do tend to be barkers, though.