VibramMen's FiveFingers V-Train 2.0 Fitness and Cross Training Shoe

Are these able to be worn in the water? Looking for a nice pair of shoes for ocean swimming near reefs in Hawaii

Where is my package?

I could be a size 8-8.5 … do I choose 8, 8us or 9?

I have the same question as someone else here: I wear 8 - 8.5, they don't have 8.5, so do I (and the other person) choose size 8, 8 us or 9?