I have been to alot of malls and most are lame and ur done in a hour so my question is would it really be worth driving almost 7 and half hours to get there?

Ya, don't drive that far unless you want to couple it with visit to Valley forge national park or other attractions nearby

King of Prussia Mall is indeed not your regular mall, and while it has several stores and restaurants the trip will be worth it only depending in what you're looking for. There are stores that offer affordable and quality clothes, whike there are several known stores if you're willing to spend money. But 7 hours and a half is a lot of time to visit stores you most likely can find closer to your home.