Sounds like the bleed screw-I would tighten it by hand and see if that helps. It will allow coolant to escape if you undo it and you would then need to refill and bleed the system-if it is under warranty I would let the dealer handle it simply for warranty reasons.
9oz sounds like a lot-if you have filled to the max when cold you will very likely see the motor chuck quite a bit out of the overflow when you warm the engine up. I think they need to register near the minimum mark when cold.
i've had my '12 STR on the rear stand for a few days while i sorted out a new rear tire for it. and it's been slowly leaking coolant. doesn't leak at all on the side stand and i didn't notice a difference in coolant level in the reservoir.
traced the leak up to the bleed screw in the upper hose, will give it a snug & see how that goes.
just wanted to let the '12 owners know this is still a possible issue.
Never a coolant leak but I did have my hoses discolor yellow . That's about it .
A set of Samcos make it proper and pretty but later caused a gasket leak for the idiots that installed them but that's a whole other matter . I love the Samcos though. The originals were just cheap.