Poorness,
Sorry for the frustration.
If you are certain that your power supply is correct (it doesn’t give AC voltage and the polarity is correct) and you are sure the ground reference that you are using for your meter is really at ground potential, then there is a good chance all the current is being shunted to ground via a short somewhere on the 9V bus. What resistance do you get across D2?
As you suspect, another possibility is the switch. Do you get continuity between C8 and the square pad of D2 (the 9V bus)?
Let me know.
Good luck.
-Brach