I see a member of EHX staff commented back in 2017 on the B9 pedal,;

It handles chords great and it has a built in leslie.
Its best to put a compressor after the B9 unless your playing is very even.
We built that into the synth9.

Can you you elaborate on that? I need organ sound and will use with keyboard, but KLeslie effect/simulation are important to me. How is this done, how doies the user switch to fast leslie=?