Tell us about yourself!
I think that a 5v cc would be enough for a few drives, but I doubt it will do for 8. And since I haven't tried hooking up my setup to that battery I couldn't tell you how to do that either. My advice would be to just try a setup with the battery and see if its enough. As long as you know what your doing concerning electric circuits you'll be fine. If 8 drives cant be powered or act strange, maybe hook 1 up first and see if that one works as it should, then expand until you hit the point where things wont work anymore. At that point you should be able to make an accurate estimation how much power you'll need.