I actually have purchased that. And also one thing I have a question on. How exactly do I set it up on a switch on my DX9?
Looks like you have done your homework!
'Auto level' would usually be 'on' all the time when you are learning. Possibly you could set up two different flight modes selectable from your flight mode switch one with auto level enabled and one with it disabled, but it will probably be a while before you want to turn it off.
'Rescue' is a bit tricky on the DX9. Ideally you want a spring loaded (a.k.a. 'momentary') switch that returns to normal after you activate rescue. The only momentary switch on the DX9 is the trainer/bind button. You can use that button but it's not ideally located being hard to reach in a panic. The ideally positioned switch is the long handled one that's positioned top left, but it's a fixed position type. You can use that switch but the risk is that you inadvertently start up with rescue enabled, which makes the heli shoot for the sky right from spoolup, which can end badly if you dont realise whats going on.
Faced with the same dilemma on my DX18 I replaced the long handled switch for a momentary switch.