Some of the things you will want to make sure you have:
A travel crate for taking him home in.
A training crate for at home.
A leash and collar. He will be just growing out of a 12" when you pick him up, so I would say the next size up from the 12". Leash should be light to medium duty at time of pickup.
Large breed puppy food. Your dog will need Large breed for the first year or until your vet says otherwise. Food is your personal choice. You can ask your vet what he/she recommends. Your pup will be weaned to eat a quality Large Breed Puppy food. There are many on the market to choose from.
I will send you a small bag, of the food your pup is eating, along for you to 50/50 with whatever you feed.
A sturdy food and water dish. Also you might want to put a "boot tray" under the food and water for easy cleanup.
Lots n' lots n' lots of
Love and Patience!