To immobilize the ankle while riding, the figure 8 straps do next to nothing My son had serious ankle problems starting at the age of 11, including a fracture and at least 3 serious sprains. We tried every kind of ankle brace on the market, and finally settled on the McDavid A101R. It is a lace up brace with nylon stiffeners. He wore that brace successfully for 4 years with no further injuries. Now at the age of 16, he no longer wears braces, and his ankles appear to be reasonably strong and able to resist injury. The key element in a brace for wakeboarding are the ability to lace up the brace tightly so that the ankle is encased in a strong external sheath. We found the nylon stiffeners to be very effective in limiting lateral movement. As the ankle becomes stronger, the stiffeners can be removed.
As far as bindings, there are no better bindings to wear ankle braces in than CWB Hinge Tech bindings. A relatively low binding like the Vapor will allow freedom of movement to poke and grab etc., while the brace provides stability. A stiff binding restricts movement of the ankle, but as an unwanted side effect, it transmits that stress to the knee, and that's a whole different can of worms.