It's a big risk. Kiteboards are much faster than SUP's so chances are:
A) the foil section is inappropriate (not enough lift) for a SUP because of the speed difference between SUP and Kite
B) the size of the foils is inappropriate (too small) for a SUP because of the speed difference between SUP and Kite
C) both of the above.
Proper foil design is largely governed by the Reynolds number (a calculation) for the foil and what you want from it (high lift or low drag). The Reynolds number depends a lot on the speed of the object in question, so a supersonic jet fighter will have a different Reynolds number to a 10 seat passenger aircraft and hence their wing sections are very different. The same applies here. Similarly, the foil will need to change depending on how much it has to lift. So if Kai Lenny is 60kg wringing wet, an 85kg paddler isn't going to see the same performance on the same foil arrangement.
That's why things like foiling moths (sailing boats) have typically 3 sets of foils depending on how much wind there is or isn't. The less wind, the bigger the foil set.