If you want to be practical and efficient, no. You would have to get into LKO, wait until the phase angles are correct, and burn out to escape Kerbin and get the encounter. However, assuming the target isn't below you, you might be able to do so. However, you would need probably hundreds of km/s of delta-v to do this, would have to get EXTREEEEEEME SPEED in order to get there before it moves, and would be much less efficient than doing what a normal space program would do. I'm certain someone can do it with cheats.