I'm in Kauai now, and did a 2-tank shore dive the other day with Kauai Down Under, who operate out of the Sheraton Kauai Resort ini Koloa (south shore) among other locations. We dove at Koloa Landing.
As you've probably heard there was a lot of rain here this winter, and you'll see the results in any shore dive. We had to wade out about 50 yards through wood chips, then general muck and the "chocolate milk" I've seen referred to here on the Board, to find good viz and clean water, but once we got past all that the diving was quite good (to this novice, anyway!). We got to 48' and had 46 min. of BT, and saw some 6-8 varieties of moray eels, tons of reef fish, and a couple of turtles even flew by (cool!).
I mentioned to my dive master that I've dived in St. Croix (awesome!!) and she "warned" me that the coral and the colors here are more muted than they are in the Caribbean, and she was right. I don't know how much of that was the nature of the reef systems here, and how much was the silt from all the rain, and I'm not complaining. It was less colorful, but just as interesting and there was more variety of sea life. To me, isn't that what's great about diving: that every dive and every place is different?
Anyway, at this point, due to the silt situation, I'd probably recommend a boat dive over a shore dive, but either way I think you'll do OK.