While I haven't tested the Motorola S9 headphones with the remote watch yet, I have noticed some erratic behavior with the wired headphones. While working out, the iPhone would randomly going into "pausing workout", then almost immediately go into "resuming workout". It would do this about 10x, until I had to remove the iPhone from my pocket, unlock it, then put it back to sleep. The workout would be OK for several minutes, then it would do it again. I had thought perhaps it was the Shake to Shuffle feature, but after turning it off, it still does it.
Unfortunately, having this disembodied voice saying to me "pausing workout...resuming workout" is way to distracting. Please post any solutions to this if anyone has experienced the same issue.