The i12 is an extremely stable craft even when rigged with a sail.
I'll second that, I've had my sail up in a fair breeze, I lean to windward for a touch of speed, not for stability. With two adults, we can switch driver and passenger with no stability issues, never went swimming from my i12s yet. My Laser is a whole different issue.
I imagine gluing on reinforced mounting patches would be a big job, and certainly not increase the portability, fold-ability or resale of the craft.
I would guess the 14 and 9 to be similar in stability.