Maybe they do possess it.. just don't allow it?
Click here for the warp calculator
Please note that the fastest Starfleet warp core is only capable of Warp 9.99. Although faster speeds are attainable, the Federation currently does not possess the technology to create a drive system faster than that.
No they don't Luke, sorry; Warp 9.97 is about it.
Travel time for one light year (1 ly) is as follows:
Warp 1 = 1*C = 365 Days
Warp 2 = 10.08*C = 36.21 Days
Warp 3 = 38.84*C = 9.37 Days
Warp 4 = 101.59*C = 3.59 Days
Warp 5 = 213.75*C = 1.71 Days
Warp 6 = 392.50*C = 22.32 Hours
Warp 7 = 656.16*C = 13.35 Hours
Warp 8 = 1024.31*C = 8.55 hours
Warp 9 = 1516.43*C = 5.78 Hours
Warp 9.9 = 3052.95*C = 2.87 Hours
Warp 9.97 = 5316.85*C = 1.65 Hours
Warp 9.99 = 7912.35*C = 1.11 Hours
Warp 9.999 = 10267.08 = 51.19 Minutes
Warp 9.9999 = 199515.9 = 2.63 Minutes (Terminal Velocity)
(C = Speed of Light, 300,000km/s)