try not to think 9X2T
but 9Tx2
meaning 9 Turns with 2 Wires
and 9Tx3
meaning 9 Turns with 3 wires
etc...
in theory they should be same speed because they are all 9T(but of course its not quite true)
if it has 2 wires the wires should be 1/2 the thickness ( then 2 wires together will be the same has 1 wire in gauge measure)
if it has 3 wires the wires should be 1/3 the thickness (then 3 wires together will be the same as 1 wire in gauge measure)
etc...
less wire = thicker wire(more punch)
more wire = thinner wire(more linearity)