Long vs short is effected by rear cassette range as well rather than just multiple front rings.
Basically no- no one (that I know of) make a clutch type derailleur for 9 speed set ups. I recently had to change to a 10 speed setup to use a Shadow+ SLX mech. So yeah, I think really you'll need shifter, mech, chain and cassette if you want to go to a clutch.