my arduino won't talk to my LED strip

Well a 9V battery is not going to do much for a 12V system. I hope it is not one of those small square batteries because they won't last very long.

The wiring looks fine. Have you tried reversing pins 11 and 13, there seemed to be some in that link they might not all be the wrong way round. It will do no harm if they are the wrong way round anyway, it just won't work.