That's the whole point of Parcher saying you should strip their hand before he resolves. The turn before, use one of your 4 Cabal Therapies (that should almost definitely be in the library by now) and sac it for Force of Will, or StoP if you suspect it (or Stifle if you really suspect that). Then, BAM you have a 9/7 in play.
Parcher, that was such a good primer that I might actually have to play this in a tournament.

