Good eye for those emission codes.
I thought, though, that 9W was basically a catch-all which potentially included analog and digital, data and voice. According to the
FCC's rules & regs, 9 denotes, "Composite system with one or more channels containing quantized or digital information, together with one or more channels containing analogue information," and W denotes, "Combination of the above" [telegraphy, telephony, facsimile, data, video].
It appears, unscientifically, that the public safety licensee community is shifting towards 9W from the previously common 1D/1E/3E combination for modifications and new licenses.