Expanded Knowledge feat
The Expanded Knowledge feat literally exists for this purpose. It allows you to learn any one power from any list, but it has to be at least one power level less than your maximum power level. So once this character is capable of manifesting 3rd-level powers, he could use Expanded Knowledge to learn hustle as a 2nd-level power.
Note that Complete Psionic also has the dimension hop power, a short-range swift-action 1st-level teleport. This character can already manifest 2nd-level powers, so using Expanded Knowledge for dimension hop is already possible. Hustle is better in many ways (real move action that could be used for other things, longer distance when actually moving), but dimension hop is cheaper and is teleportation, which can be useful.
Note our Q&A on moving while still full-attacking—the section on swift movement could be very useful to this character. The best way to do this is the Travel Devotion feat from Complete Champion—and the best way to get that is through a single-level dip of the cleric class. May not work for this character, but a cleric level is excellent—easily worth trading in a level of fighter or rogue for.
Generally, shadowmind is a very weak prestige class. Its unique class features are exceedingly weak, it has a lot of dead levels, and the levels when it gets sneak attack, it doesn’t get manifesting—you could literally do better just alternating levels of rogue and telepath. You would get better class features and far more skill points.
Similarly, rogue does not offer much beyond its sneak attack progression until 10th level—taking 8 levels of it is kind of pointless. Other classes get sneak attack, and better class features. A few levels of rogue—say, 1-4 levels, since 1 and 3 give sneak attack and 2 and 4 give OK class features—is closer to what this character should be aiming for. In particular, the penetrating strike ACF in Dungeonscape replaces the 2nd-level evasion feature with the ability to deal half your sneak attack damage against things normally immune to it. That is very nice. Uncanny dodge, at 4th, is... OK. Not great; I probably wouldn’t bother.
I’m not sure what the character is using the fighter class for, but unless absolutely desperate for feats, it’s probably not a great pick. Even if the character is absolutely desperate for feats, two levels of psychic warrior, instead, give the same bonus feats (off a list expanded to also include psionic feats!), plus a couple of powers known and extra power points (note that all manifesting classes share power points, so those power points can totally go towards your telepath powers).
Thus, for a manifesting sneak, other options could be better. Telepath is fine; egoist or nomad might arguably be superior, but telepath certainly has quite enough going for it.
Now then, what to take instead?
Well, first of all, note the existence of the psychic rogue. It’s Intelligence-based, has its own powers and power points, and still gets sneak attack. Somewhat slowly, but it’s there. An 8th-level psychic rogue has all the relevant class features of an 8th-level rogue, at the cost of somewhat fewer skill points and 1d6 sneak attack damage. In exchange, six powers known (three 1st-level and three 2nd-level). Psyrogue even gets hustle as a power, albeit sadly as a 3rd-level power (could have it if you took that 9th level). Note, however, that the 8th level itself gets very nearly nothing—no class features, no powers known, just 2 PP.
If the character can justify any religious or spiritual devotion at all, dipping cleric for Travel Devotion should definitely be considered. Since the 8th level of psyrogue is pointless, you could easily change Fighter 2/Rogue 8 into Psychic Warrior 2/Cleric 1/Psychic Rogue 7 and lose almost nothing. This allows the character to move, as with a move action, as a swift action for 1-3 minutes per day (depending on the character’s Charisma, since it is powered by Turn Undead).
But we can go further. Since Fleet of Foot and Run are terrible feats, and we’re getting better maneuverability through psionics and/or devotion, we can free up two feats—which means we don’t need fighter or psychic warrior at all. This could easily be replacing the Fighter 2/Rogue 8 with Cleric 1/Psychic Rogue 9; that gets us a 3rd-level psychic rogue power, which could be hustle. Alternatively, two levels of regular rogue gets us more sneak attack, more skill points, and that excellent penetrating strike ACF I mentioned earlier.
Swordsage, from Tome of Battle, is also an excellent option, particularly if taken at exactly 9th (character) level: you can take the assassin’s stance for +2d6 sneak attack damage in one level. It’s got lots and lots of other goodies, too, like cloak of deception (greater invisibility for one turn), shadow jaunt (50-foot teleportation as a standard action), and mountain hammer (ignore all DR and Hardness for one attack that gets +2d6 damage).
You could also use ardent, which with Practiced Manifester can actually select higher-level powers right from 2nd level (not 1st because you need a level of ardent in order to select it with Practiced Manifester). Not the best way to get hustle, but it could get you dimension hop at the same time, which is nice.
Or we could just go with more/earlier telepath levels. Losing some sneak attack for better manifesting is a rather-good trade, though we also lose a lot of skill points that way. But even just the two more levels of telepath means that Expanded Knowledge could get get us hustle as a telepath power.
Complete Scoundrel has the uncanny trickster, as well as the magical trickster which has a psionic adaptation. These can progress your telepath manifesting (on two out of three levels each) while granting some class features and far more skill points.
Alternatively, the cognition thief is a weird prestige class from Player’s Guide to Faerûn that progresses manifesting (poorly), has some fairly-solid class features—including the ability to poach some powers from the telepath discipline list. This could replace telepath altogether, allowing you to run as a pure psychic rogue who picks up some telepath powers this way.
Other prestige classes worth considering include daggerspell mage (Complete Adventurer includes a blurb about adapting it for psionics, though this is going to take a bit more work than the author suggests) and ebon saint (Complete Psionic). The shadowmind... is easy enough to enter, I suppose, but it gives so little. If you were taking concealing amorpha anyway, one level is basically a free power, even if it’s not a great one...