I drew the conclusion from the questions and answers above. Being able to statically pan two separate delays is not exactly a stereo effect in my book. In addition I find no stereo related knobs in the GUI's and all the delay demos I can find are in mono.
But again, from what you are saying it sounds like the ping pong effect belongs to a dedicated algorithm rather than being a global setting for any of the nice delay types? If that's the indeed the case I personally see no purpose of the H9 as a delay pedal.
Well, all Delay algorithms can work in either mono or steoreo. The Delay Mix knob is not a simple panning knob. Here is what you can find in the description of each delay algorithm in H9 Control. You can click the "Info" button to see the description of each algorithm in H9 Control.
Delay Mix – [DLYMIX] : Controls the relative level of the twin delays, Delay A and Delay B. The H9 has circuitry that detects which input/output jacks are being used and adjusts the routing of signals through the Effects algorithm accordingly. Dly Mix’s mixing behavior depends on whether you’re using mono or stereo outputs. For Mono Out, with [DLYMIX] = A10+B0, output 1 will have only Delay A’s contribution. With [DLYMIX] = A10+B10, Output 1 has an equal amount of Delay A and Delay B. With [DLYMIX] = A0+B10, Output 1 will have only Delay B’s contribution. For Stereo output, with [DLYMIX] = A10+B0, BOTH outputs will have only Delay A’s contribution. With [DLYMIX] = A10+B10, Delay A goes to Output 1 only and Delay B goes to Output 2 only. With [DLYMIX] = A0+B10, BOTH outputs will have only Delay B’s contribution.
So you can adjust the Delay (A&B) and Feeback (A&B) for each channel (A&B) independently. What does a stereo delay do in your effect book?