Are you sure V9 is SA only?This detent plate converts your V1 to V9 -- Single Action Only. This what you want? There is no way to decock the pistol other than dry firing once this plate in in the pistol. Also used for LEM models where you want to retain the Safety (ya gotta use the lever too).
Note in Step 2 (above) the detent plate in the pistol can spring out wildly. Ease it out so the spring and detent slide stay in the pistol. A lot easier when reassembling.