Thinking about getting a pitbll

Hi

 I work 8 hours a day but not on weekends. I have a 4 year old daughter and a 20 year old daughter. I am thinking about getting a pitbull pup. Of course I know if you raise a dog to be mean then they will be, but what I worry about is leaving the pup alone for that long during the day. I do get an hour lunch though so I would come home in the middle of the day to play with it then...Does anyone have experience with the pup or dog being alone for 8 hours a day? We live in a duplex, right across the street from a park though so we would go there daily so it could get exercise....