EHX people have sometimes stated that their pedals need 9.6v, and their wall warts supply exactly that. Some people say that it is the voltage which a 9v battery supplies in reality.
I would be scared of powering a Boss, Ibanez or MXR pedal with an EHX power supply. Since the limited knowledge I have says that pedals don't mind being supplied more mA of current, but more voltage is a cause of frying them.