AC Adapter gives much more voltage than it's supposed to
Obviously, you have an unregulated power supply. If it's rated for 9V@600mA, and producing 14V2@Open.
To test for its output while driving your pedal, take the cover off your pedal (usually a trivial matter of removing a few screws); plug in the wall wart, then connect your meter leads to the pins of the peda's power jack. This will show you the highest voltage it's pushing into your pedal &amp; let you get a better idea of how much to worry.


Remember, for most electronic equipment, overcurrent is more damaging than overvoltage. The only time that overvoltage without overcurrent is likely to damage equipment is when it exceeds the breakdown voltage of a component; most manufacturers will likely eaither include their own Vreg in an expensive piecd of equipment, or spec all their components to have a much higher breakdown voltage than the 'nominal' input voltage.