12 Track Vs 9 Track Standard Cell

one track is approximately the minimum spacing between metal1 and metal1 via in a technology node . Track is generally used as a unit to define the height of the std cell. a 12 track cell will be taller than a 9 track cell. a 12 track std cell will be taller , that means more metal1 routing space is available within the cell, hence cells will be faster. where as in a 9 track cell, the cell will be compact, but speed is less compared to 12 track.
9track -> less area, less speed compared to 12 track
12tarck -> more area, more speed compared to 9 track