Is there any reason you want a 9V? After mistaking it for a Lantern battery, I looked it up on wiki. They even have new primary lithium versions of it and I'd think 9 whole volts in a relatively small package could produce quite a bit of power. Even 0.5 amp = 4.5 watts worth.
So I am curious how come there aren't several keychain/EDC sized lights that use them. Maybe it is because there is no easy way to connect the positive/negative terminals in a flashlight. Most 9V devices you have to plug in a cheapo plastic-covered lead that goes to 2 small wires (which isn't conducive to high current flow).
