I have 2 x H9’s and a TF and am just controlling with aux switches. Cheaper and you can assign everything through h9 control. I would check out the options in H9 control app Aux switches to see if that’s all you need before going midi. If you need more than this there are quite a few small pedalboard friendly midi controllers in the market like these:
http://www.tech21nyc.com/products/effects/midimouse.html
http://www.disasterareaamps.com/shop/dmc-3
http://www.one-control.com/gecko-midi-switcher.html