1. 18 dB input level seems like a big boost. Again, I'm asking what is your top level on the meters in H9 Control without any input gain applied? Also, what type of guitar/instrument are you using?
2. What exactly do you mean nothing works now? Did you change anything in your setup? The only way I can help is if you're specific and detailed in your response. A step by step guide that either reproduces or demonstrates the problem(s) would be most useful. Or better yet, a video of what you're experiencing.
3. How are you connected to the pedal, mono in mono out, mono in stereo out, stereo in stereo out? If mono in mono out, make sure you are plugged in correctly to the Input 1 AND Output 1.