Pin 9 is a common earth for pins 5 ( electrical ariel ), 8 ( backup for saved info ), 9 ( illumination when your lights are on ) and pin 10 ( main supply to Bose unit ). Your problem is no supply on this pin ( pin 10 ). Check pin is sitting correctly in plug ( is pushed in fully )and the fuse for this supply is not blown. There are 2 other fuse boxes in the engine bay at the bulkhead behind the battery.