I have a couple of power supplies for laptop computers. Most are around 18V and 2.5A, and they generally have removable power cords!
You can find them for free with even the most limited scrounging ability.
Any LM338 chip ( again, very scrounge-able, old VCRs are full of them, or heck, you can blow the $2.00 and buy a new one I guess) a couple resistors and caps and you have a buffered 9V pedal power with all kinds of headroom!!!
Nifty.