Yes, the Serenity is a very amazing concept!
It's both fast in light winds and very graceful, slicing over the water and through the chop like a scalpel.
The Serenity does not really "plane" (although I suspect that depends on how you define "planing" ) but the bow wave does move back when you get it going.
Your 10 m2 sail would not be needed on the Serenity, but you can certainly use a sail that large.
The Serenity "glides" over the water so easily, it does not really need a large rig.
7.5-8.5 is as big as I would ever consider, but I've sailed the Serenity with 9.0 m2.
Problem is the larger rigs are a bit more difficult to balance, and the
Serenity is a bit challenging to balance on in the transitions.
It's better than formula wide boards because it glides along in winds
(2-7 knots) that won't get the wide boards planing, even with the largest rigs.
The Kona is probably a better board for higher winds, but the Serenity sails circles around the Kona in < 6 knots.
Hope this helps,