I remember reading an interview somewhere that steve said that when he is playing fast the ts-9 does not track well so he is switching to the ds-1.
I think it's the other way around.
Anyway, here's Ibanez's press release, which clarifies the 'identical distortions' mistake.
Ibanez Debuts The Jemini Steve Vai Signature Effects Pedal
The latest Ibanez 'must-have' was small in size but hard to miss at the Ibanez NAMM booth in Anaheim. The multicolor die-cast zinc case of the new Steve Vai signature distortion pedal makes sure it will stand out on even the most crowded pedal board. "However, some players may need less pedals in their rigs if they have a JEMINI," said Lucian Tu of Ibanez. "The JEMINI is beyond versatile, with both TS9 Tubescreamer overdrive as well as the classic distortion tones long associated with Steve Vai. So you can achieve anything from just a subtle bit of overdrive boost to completely full-blown, all-out distorted tones.
Both the distortion section and TS9 overdrive are all carefully Steve Vai-tweaked and modified, the result of information gleaned from extensive touring with proto-types and constant consultation between Steve and our designers during that time."
The JEMINI's unique multicolor casing features on-off LED lights that surround the control knobs for exceptional visibility as well as a Vai symbol on the footpedals. The list price is $285.70
For more information, visit their web site at www.ibanez.com