I'm a Philly girl too. Good luck with your interview. Reading Terminal is wonderful, and there is a fabulous little cookbook store called The Cookbook Stall.
I am always paranoid about being late to interviews. I too would plan to catch a cab at 9. Some mornings, 76 is really backed up, and 676 can be miserable too.
Where exactly is your interview (street names)? There is some great shopping within a few blocks of the Convention Center, if you like to walk. You could venture up Market Street, hang a left at City Hall and head down Broad Street towards Walnut. At Broad and Walnut is a wonderful Williams-Sonoma. Turn right onto Walnut and you'll find a few blocks of fun boutiques, leading you right to Rittenhouse Square.
Shelbygirl, we live very close to each other. I'm in East Falls. Before that, we lived near the Art Museum.