Sorryif I'm asking too many questions, but why? Not arguing with you or anything, I'll definately switch power sources. I'm simply curious as to why the 9v is bad?
The standard 9V battery is a stack of AAAA size batteries connected to give the total 9V. The AAAA sized cells have very little capacity for current. Laser diodes need more current than the 9V battery can give effectively. It will work, just not for very long or (maybe) not up to the needed current for full output.