I hear this is possible to do. Basically control all the virtual knobs of the H9 with a ‘factor pedal’s physical knobs. Is there a document or video on the setup of doing this?
You want a regular MIDI cable, which is a 3 or 5 pin DIN cable, available on line or from an electronics shop (they are used for audio as well). Connect it from the Factor's MIDI OUT to the H9's MIDI IN. The plugs should look like one of the pictures below.