Why is my dog doing this?

My dog is a pitbull and we just got him from foster owners. He wont settle down and is really acting up. I suspected he was homesick so i took him for a very long walk, and tried to get him oriented and i've been erting myself by scolding her on everything that she shouldnt do such as putting her paws on the window and looking out and weeping, she was chewing on a ball and started getting real rammy and when she did something goood i comforted her by petting her. She loves to go for walks but once she gets back into the house she starts getting upset and restless. Right now she is on my couch snuggling with my dad ( very good thing) but im pretty sure this will happen again for a while. Is there anything i can do in the future when she starts acting up? She is a very sweet dog and was being very friendly to us and strangers when we were walking. Also, my pitbull isnt trying to attack my cats but she is not exactly ignoring them either. My cats are terrified, will my cats get used to him or do you think its next to impossible to get the two to be comfortable with eachother?