If fresh water were -9 degrees F, I suspect it would be solid ice (it could be super-cooled if it were absolutely still, but lakes and rivers are not that, and splashing in super-cooled water would turn you into a popsicle). The air temperature isn't even that cold in any of these pictures.
Actually if you read the link you'd see one of the polar bear events the temperature was -8 degrees fahrenheit. I've watched similar events on TV where they actually cut a hole in the ice to begin the event.
