Possible to hide or de-prioritize an application from spotlight?
Spotlight learns from your actions. The more you choose QuickTime for a certain input, the more that result will appear as the Top Hit for that search phrase. Try typing your phrase which shows QuickTime first, then choose Quicken. Keep doing this and it will learn that you want Quicken instead. This might take a few tries depending on how many times you incorrectly taught it first.

Alternatively, you can prevent something from appearing in Spotlight by adding it to the Privacy list. Open System Preferences → Spotlight, choose the Privacy tab, then drag QuickTime Player.app from Applications into this list.