I would suggest that you find another pedal.

If its range is 2-12V and given that the 'Factor will clip at 3.3V, you will only have an effective swing of 2-3.3V, meaning that it will not get near zero, and the top 75% of the pedal will do nothing.

The 'Factor will draw about 3 mA at 12V, so it will probably not damage the pedal (check wih manufacturer to be sure).