Every app must be specifically ported to every BB model and major OS level combination. That's quite a number of combinations, and many developers choose to not do so...rather, they choose to support a subset. From what I can see on the AppWorld catalog page, the waze developers have not ported to the 9900...and only they can answer if they indeed ever intend to.
Occam's Razor nearly always applies when troubleshooting technology issues!
If anyone has been helpful to you, please show your appreciation by clicking the button inside of their post. Please click here and read, along with the threads to which it links, for helpful information to guide you as you proceed. I always recommend that you treat your BlackBerry like any other computing device, including using a regular backup schedule...click here for an article with instructions.