Hi pingopilot and welcome to seabreeze. I've owned both boards and the icon is better for flatwater. If you can I'd purchase something longer for flatwater if that is al you will be using the board for. But in saying this if you want a board that surfs well and you can use in flatwater definately go for the Icon or look around at other brands. Hope that helps.

Naish 9'3 works well as you, i do more flatwater, because the surf here in Noosa is usually flat,

my weight is 95kg, height 5'11", unfit, not a surfer before. I came off an 11'6" Southpoint onto the 10' Icon a few months ago. It floats well and should be fine for your weight. The swallow tail is a little less stable but you get used to it quickly, much better for sink-turns. It surfs great (at least with my meagre ability). It paddles fine on flat water, without too much yawing, but is a lot slower than a longer board. I wouldnt want to be doing a 10km flat water epic on it unless you're not in a hurry.