>We dance Strip the Willow in 9/8 with a running step.
Not in Scotland they don't except very infrequently in an RSCDS class as an
exercise and not one that will find a lot of favour. At a ceilidh you will
almost certainly dance it in 6/8 time and the music may change to reel time
half way through.
As to why that should be, I look forward to the views of others.