What is your motherboard type? 33? And what is the origin of your firmware? Again, I can't attest to what's currently in the Marlin repository, but D9 used to be on IO 9, hence the D9 label. What suggested to you that D9 is on 16? There at least used to be a lot of ways one could mess up the pins.h file - you may want to attach the entire file for an independent view of it.