My answer would pretty much have been the same as yours.
vorpX uses a certain amount of the CPU while checking for newly started programs, but under normal circumstances that should be below 10%. The OP’s 25% may not be as bad as it looks though. Modern CPUs clock down heavily when idling, so if those 25% are shown in a clocked down idle state, it’s still almost nothing.
If not, closing vorpX or pausing the watcher is indeed the best thing to do.
BTW: While running games with vorpX the watcher always pauses, so no CPU cycles are wasted while playing games.