Thing with putting batteries in pedals that are on boards is that they drain current as soon as there is a jack in the input. If you don't unplug the lead from the input jack then it will drain the battery in a matter of hours even though you're not playing through it, whether they're switched on or not.
Having to unplug each individual pedal after a gig kind of negates having a board in the first place.
I've heard of people using USB power cells with a booster to give 9vDC, but haven't used one myself.