This one says it can charge faster at 9V, but your device needs to support the "faster" charging Qi standard that they do not say which version they are using. Either way, be aware that the 9V is the charger that power the device... not the voltage that is feeding wireless the device being charged (therefore don't bother with your device, if it's a recent Qi compatible).

@robertt, you can add more stuff to the hunt if you wish. It will enrich it.