VR-1s have an aperiodic release system so the hole in the back isn't really a port. This makes it suitable for use close to a wall. The problem in a book case would be diffraction from on top of the tweeter.
If you can get your hands on a pair of LCR-15s which are MTM, they would do much better than VR-1s in such a placement IMO. They are really designed with the possibility of being tucked in to a rack in mind. Your shelves can easily accommodate them by the looks of your pic.
Good Luck!