Since the biggest problem with doing an Alaskan cruise is packing enough clothes without overdoing it you'll be fine without the hiking shoes. We went in Aug. both times & all I took was a hooded sweat shirt & was comfortable. You can always pack a light sweater & wear it underneath. Of course it does get a little cool near the glaciers but you can always duck back inside to get warm for a while. For the formal nights I only pack a long sleeve dress shirt- no jacket & dress pants and it's always been accepted. Leaving the jacket behind will save lots of room in your suitcase.
Jeans were OK on casual evenings with a polo or Golf shirt. I've bought a rain suit a few years ago but still haven't had to use it.