[Help] How do I introduce my new puppy [F] to my current dog [M] without him attacking her?

I am picking up my new pitbull puppy on Friday. She is 9 weeks old this Wednesday and her foster parents told me she's already a little skittish. I currently have an 11 year old pitbull who we rescued at 3 weeks old and he has never in his life been in close quarters for very long with another animal. We're getting our new puppy because we feel that in his old age he needs a companion and we need a companion as he ages and one day in the next couple of years passes away. The problem is that the one time he has ever had an interaction with another dog it was a pitbull who attacked him and he's been pretty well traumatized ever since. He's never actually attacked another dog before but his mannerisms just spelled trouble for us so even when we walk him he's on a very tight leash and if we see other dogs we usually just hold them between our legs and fear that he's going to try to attack them. He's extraordinary friendly would never hurt a human and he's wonderful with kids. I know that with time he and our new puppy will get along just fine once he accepts her as part of the family. I'm just needing some advice on the best ways to introduce them to each other so that he handles it well and she isn't terrified. Anything you guys could give me would be great thank you so much. via /r/dogs http://ift.tt/2sOU9R8