Also temember that balls are shy, nocturnal creatures attracted to tight warm places. If you have the traps out in the open (of the attic) and it's still daylight, he could very well have decided the food is too exposed to be tempting and gone to find somewhere else to curl up instead. Make sure the traps are somewhere you can find/get them but also not in the middle of an open space where he wouldn't want to go. If you have heat sources, traps near those will likely attract him better.

I dunno the risk for leaving bps out, but when I had rodents that got loose I checked every hour and very rarely found them farther than under the radiator next to the cage. If you don't have any animals that will eat a bp and there's not as much risk of electricution/them hurting themselves as is for rodents, then you might be able to wait until night or even next morning, though I'll leave that up to the more expierenced bp owners to tell you.

If you really want to be thourough (and messy), you can put down a bit of flour in places he's likely to be. If you find slither marks, you'll have a better idea of where he is. That you can definitely leave until the next morning to check since he's going to be active mainly at night. Remember he's probably startled to find himself suddenly out of his cage that was fine tuned to his needs and is likely to be looking for a good replica. :3