I dont understand this fear
If you have a "thing" with all things in the ocean, yes.
But most dont, and on the westside as said, there are no issues at all - they are there maybe, but dont go after you.
On the eastside (Muizenberg and vicinities) there are shark watching just like many other spots around the world - and there havent been any attack (well, error bites) as far as I know, except for some who completely disregard the flags.
And the "false" bay at Muizenberg is not interesting for kitesufing whatsoever (wind not sideshore) - but good for surfing because of the warmer water and easy access.
We have been down there many years now, in the summer (January/February) - and having a great time without worrying.
A kitecam picture from last month when we were at Dolphin Beach (and all around the "cape") :