Yep, Elon Musk has publicly mentioned that it will light up the engine to boost back to the launch site.
>So, I think, there's a number of improvements across the board, in structures, avionics, engines and then, as I said, this version [the Falcon 9 1.1] is really designed to be able to have the first stage come back - boost back – to launch site, deploy landing gear and actually land propulsively.[1]
With a flyback stage the optimal separation altitude and velocity drops, and the second stage gets even larger to compensate. But yes, the engine will cancel the downrange component of velocity and reverse it. Since the stage is empty the fuel requirements are actually quite modest.
>So, I think, there's a number of improvements across the board, in structures, avionics, engines and then, as I said, this version [the Falcon 9 1.1] is really designed to be able to have the first stage come back - boost back – to launch site, deploy landing gear and actually land propulsively.[1]
With a flyback stage the optimal separation altitude and velocity drops, and the second stage gets even larger to compensate. But yes, the engine will cancel the downrange component of velocity and reverse it. Since the stage is empty the fuel requirements are actually quite modest.
[1] http://shitelonsays.com/transcript/crs-2-post-landing-teleco...