As the BK9 doesn’t have aftertouch, I’ve had to find a workaround. But it will also work for the E80 if you find aftertouch difficult to control:

Edit the solo voice to have vibrato (bring up the depth control in voice edit) then add the delay so it only comes in after a while. How long kinda depends on the tune, but you’ll get a feel for it. This way, you can play quick passages without the vibrato, and it will only come in on longer held notes, which is kind of what a horn or string player would do.

If you get the aftertouch working, you can still combine the two methods, so if you want the vibrato immediately press harder, if you just want the normal delay let the delayed LFO do its thing… 🎹😎