We’ll call it preset 15, so that switching from preset 14 (some random reverb) into 15 will then mute signal and go into the tuner mode before the next song starts). There’s no issue with having the tuner mute everything, but rather having it as “on” when switching to the preset.
There’s only one way of doing this and it involves sending two commands from your MIDI controller. One message to change to Preset 15, another sending a CC# that toggles the pedal into tuner mode. If you want the tuner to mute the audio, this must also be set in the pedal’s System Settings. There’s no way to recall the tuner as a preset.
First thing you have to do is go into H9 Control > Pedal Settings > MIDI Settings > Assign MIDI CC messages to pedal functions > Toggle Tuner > (assign the cc# of your choice in order to put the pedal in tuner mode).
Second, go into Pedal Settings > Tuner > (on the bottom right you’ll see a button that says either “Mute” or “Thru”). If you want the H9 to let your dry signal through while you tune, set it to “Thru.” If you want the H9 to mute all signal while using the tuner, set it to “Mute.”
Now, on your MIDI controller, whenever you press a button to recall preset 15 on the H9, send a MIDI message with the CC# to toggle the tuner along with the program change. This way, the H9 will change to preset 15 and right afterward recall the tuner for you.
Or did I totally miss what you were talking about?