I started my foray into UI testing on iOS with Frank a few years ago. I tried a number of different approaches and contributed back a few times to the project. Overall, I think I used it on three different apps (I worked for a consulting firm at the time).
About a year ago I tried something new and experimented with KIF, Subliminal, and UIAutomation directly. They each have their own pros and cons (see this Github repo  for more details). Unfortunately, not a single one could do everything I wanted or was reliable enough to use on client projects.
At the end, I ended up doing feature level tests per controller via a BDD-style framework because it proved to be more reliable. Obviously, it isn’t as close to user interaction as these frameworks are, but it was good enough. You also couldn’t do anything with “system alerts” but that’s a whole different story.
While it might be difficult to upgrade your existing [insert third-party feature testing framework] code now, I think in the long run it will pay off ten-fold. Apple changes their internal APIs with every release and the best a third-party library can do is rush to keep up. I would imagine that all three are struggling right now as I doubt any of them work out of the box with iOS 9.