I tried guitar –> H9 –> amp with no other pedals. I used two different guitars. On both the bypassed signal was significantly louder than the effected signal for a wide range of settings and different presets. I tried it with the mix at 50/50 and the clean signal was much louder than the dirty signal.
My bass was a little harder to tell—levels seemed a little more comparable, and the EQ made a huge difference. I only tried one bass.
So what CrushStation presets are you using, and what are the settings? This might matter b/c your guitars could be sitting on the compression curves and gain curves differently depending on their input levels. Also have you tried adjusting the input gain of the H9?