Not sure what the KS9 can do on phone calls and streaming, but the KS8 can attenuate the microphones when you are streaming or pick up a phone call. The default is 30% attenuation, but it can be adjusted. There is also an on-off switch (in the programming software) for adaptive volume. If the surrounding sound volume goes up and down the adaptive feature increases and decreases streaming volume to suit. As a last resort there is also the hardware buttons on the side of the iPhone to adjust volume.
I find the iPhone app useful for changing programs, but I have a total of 9 programs. With a small number of programs it is probably easier to just use the aid buttons. The other use I have of the app is a manual adjustment of the microphone focus in difficult listening situations. The app is probably where your battery indication is, but with a zinc-air battery, it is pretty much useless. The battery stays at a constant voltage and then drops like a stone within minutes once it starts to die. I just get a battery out to air up at the first battery warning tone. I never look at the battery status as it is pretty much meaningless.
Hearing aids increase the background noise levels that one does not hear with impaired hearing. That tends to mask tinnitus.