Is it possible to connect via midi two h9 and then a Line 6 m5 and load presets simultaneouslywith an auxswitch in a h9 or I need a midi foot controller?
Yes, if you assign the aux switch to trigger the pedal functions "Increment and load preset" and "Decrement and load preset" and you turn on PGM.XMT, the first H9 will send out program changes when you change its presets with the aux switch. If you configure the second H9 to use the MIDI Output Mode "Thru", it should relay these program changes on to you Line 6 pedal. You can do most of this configuration in H9 Control. PGM.XMT is the only thing which you'd have to configure on the H9 itself in its system settings.