The larger issue will be getting an Uber in a smaller market at a time when you are likely competing with many others.

To me, this is way too close and WN probably faces multiple no shows on "cruise days" so it likely deals with those on a uniform basis. The larger problem will be availability on later flights rather than simply the fare.

I would book the later flight and then change if it is doable when you get to the airport and can assess the situation.