What about 9 at Pasatiempo? Before the clubhouse was built.
That's a great suggestion. Could be it. Pasatiempo isn't that sandy, but the soils do look white in old b/w photos.
There were actually two different ninth greens at Pasatiempo in the early years - the present one and another that was straighter up the hill. This view would have cut out the other green even if it was extant at the time the picture was taken. The bunkering, for the current green, is pretty much correct.
I also like the suggestion because MacKenzie didn't stick around many of this courses from the second half of his career for long enough to autograph a picture of the finished product, but he lived at Pasatiempo.