My wisteria has yellow spots (most with a very tiny brown center) on most...
The spots on your wisteria are uncommon and probably brought on by the unusually wet cool weather this year. There are only a few normally minor leaf spot diseases known to occur on wisteria, but yours does not appear to be affecting the health of the plant so we do not recommend any action at this time. Wisteria is extremely tough and should come back fine next year for you.
If you want to, in the fall when the leaves fall off, you can rake them up and dispose of them off site to remove the excess disease-bearing material in the area.