The file cape-headers.png that is on the default webpage of the Beaglebone Green has the P8 and P9 headers mixed around. Looking closer one can see what happened, The P8 and P9 text is pointing to the headers on the image of the board, but then the pinout in that same image is for the other header. Very confusing, I had already started down a slight wiring redesign due to this image. Double checking some other sources tipped me off to my mistake.
To clarify, the image is correctly identifying the headers. It is just very misleading in it’s position to the pinout in the same image.