There is an option in H9 Control where you can set "Midi Over Bluetooth" to be on.

Select "Pedal" on the bottom toolbar, then "MIDI Settings" then "MIDI over Bluetooth".

But I guess it would depend on the app you are using and I have never used Bandhelper.

Another thing to be aware of is that there is a limitation to the number of Bluetooth devices you can connect to an iOS device… it seems to be 3 on a 32bit iOS device and only 2 on a 64Bit iOS device. (iPhone 5S, iPad Air and iPad Mini with Retina)

I have an iPad Air and a iPhone 5S (64 Bit)… I can only connect 2 H9's at a time … but when I use my Wife's or Daughter's iPad Mini's (32 bit) I can connect 3 H9's

Unfortunately this does not change in iOS8 (at least at the time of writing this and testing the latest Beta)