I've been going to St. Croix to dive since '07, it's fabulous! In talking about the long swim out to the wall at Cane Bay, no one mentioned the fact that if you drop down about 50 yards out, there's lots to see, you don't need to kick out all the way to the buoys.
Regarding the pier, I don't think I've ever had a dive there that I didn't see at least one octopus or seahorse. I've even seen three dolphins cruise by at the pier, not to mention frequent eagle rays, ALWAYS turtles, so many interesting juveniles...it's probably my favorite place to dive!