First, please note that the ToneWoodAmp is a stand alone device that has its own DSP for effects (reverb, delay, echo, tremolo, etc.). No iDevice or Android device is needed for these effects to function.
In theory, iDevice would work on Android, but the problem we're currently facing is the Android platform does not at this time have any support for Virtual Midi, which is required for the apps to process the effects back to the ToneWoodAmp in real time. Google announced this year (2017) that they're working on it. As soon as it's supported, you'll start to see Virtual Midi apps popping up in the Play Store.