One of the ways that the Falcon 9's attitude is controlled is through thrust vectoring of the main Merlin engine(s?). In images of older thrusters i've seen hydraulic or electric linear actuators to adjust the angle of the nozzle such as in this vernier motor however I can't find any concrete info on how this is achieved in the Merlin class of engines. The closest I could find was an entry on wikipedia which states that:
Propellants are fed via a single shaft, dual impeller turbopump. The turbo-pump also provides high-pressure fluid for the hydraulic actuators, which then recycles into the low-pressure inlet. This eliminates the need for a separate hydraulic drive system and means that thrust vectoring control failure by running out of hydraulic fluid is not possible.
The Merlin engine for Falcon 1 had a movable turbopump exhaust assembly which was used to provide roll control by vectoring the exhaust
I'm not quite sure what to make of these entries. Does this mean that the thrust vectoring is achieved through 3 hydraulic pistons similar to the 3 electric 'pistons' in the Vernier Motor? Also can all Merlin engines thrust vector and what's the thrust vectoring capability of the capable Merlin engines (in deg)?