There are prolly different ways to do this. Here are my thoughts …
I think there are a few variants of this effect. In both cases the dry signal is always there and the exp pedal selectively applies the delay or reverb. In one variant, the effect is totally removed with the treadle at the heel position. In the other, there is still some effect in the heel position (it’s just that more is added when the treadle is toe down). I have attached H9 screen shots for both variants where the effect is delay. The lower end of the range in the PitchFuzz example is about 1.1 or 1.2. You can convert this to the other variant, by using 0.8 instead (or you can even go lower … even to 0.0) if you want.
This should work in the H90 using one of the two preset slots. The second preset slot is still available for use and these two slots can be either in series or in parallel. Obviously, this is delay. I haven’t done this in the H9 with reverb (or even tried).
The H90 obviously can run the two different paths in parallel. I’m guessing that that fact allows you to create this effect with virtually any reverb or delay. One parallel path is dry (or maybe modulated or distorted if you want). The second parallel path is mix =100 reverb or delay and the preset input parameter (in the General parameters section) is controlled by the exp pedal. It needs to range from something really low to about zero dB. That should allow you to selectively apply reverb and or delay like on the video.
Good luck.
