I'll layoff the iSonic recomendation based on reading between the lines of your plug+play comments, although the iS will certainly suprise you on just how P+P it can be for a full performance raceboard...
That tilts it back to Futura as the next "most efficent" (important for that light wind range) design in our range, normally I would agree with the 122 for your weight in 10+ to 15 range but if you feel you will be spending a lot of time in (or near) 9 kts or if that 9kts is anything less than "solid" 9, and considering your comments on wanting to be planing all the time, then the 133 would be an even safer P+P option in the light end and still be readily manageable by light riders in 15 kts.
Again, the 2 or 3 fin option is essential advice (yes, they can plug and play)
To keep it simple, having a "low wind" and "high wind" option makes it easy.
Making the wrong fin choice, or being caught out in changing conditions (in that range) will never be fatal, merely less effective, but your overall enjoyment (session success rate) will have to better, especially when covering that wind range with one board.
Cheers ~ Ian