you're looking for what's called a clicky tailcap, but unless you are mounting it on a rifle, I wouldn't recommend a clicky for tactical use, as with adrenaline, you might lock the light on, thus making you a really bright target, drawing enemy fire, etc etc.
but anyways, you might need a new LA. In the 9P you need to replace it with a P90 or P91, the P91 being brighter than the P90, but with approx one third the runtime. the 9P's Lamp assemblies are just that, assemblies, the contact spring, reflector and bulb need to be replaced as a whole, the lamp cannot be replaced separate from the reflector and the rest of the assembly. before you swap the lamp assemblies, try new batteries, sometimes that does the trick, also, be SURE that you DO NOT get a P61 or P60 for use in your 9P. the voltage of the three batteries is too much for the bulb to handle and will explode or just not work, something you don't want, I'm sure.
so, in review:
you want a new lamp assembly: the P90 or P91 from surefire will work fine
you also want a clicky tailcap, there are several, the Z59 and Z49 are black in finish, but the Z59 is a tad more matte in its finish and more durable than the Z49. the Z49 however, has a rubber crown on the end of the tailcap, thus making it be able to be used for tailstanding, but I don't think you would care about that in tactical use. I got the Z59 for my G2, works great, love the clicky(more personal preferance as far as clickies go, though) but be careful if you get a metal accessory for a plastic bodied light, as it is insanely easy to shave off the threads with the metal accessory, luckily I saved my G2's body, but I still need to be freakishly careful whilst putting on said tailcap.
Hope this helps, and I hope I didn't bore you,
Flash
:EDIT: wow I took a long time to type that, KeyGrip beat me to it
