If they do anything for the boosted 90 starting quests like they did with Monks & Proving Grounds tech, I doubt it. They'll probably start off better than a leveled 90 since it will have actually pointed out how to use their different abilities rather than just shoving them somewhere in their spellbook each level.
And I highly doubt they're going to pass up on the opportunity to use the Monk-esque quests and proving grounds tech.
My best guess (and I could be wrong) is that boosted 90s are going to learn more about their class in the opening quests than those who leveled from level 1 (excluding monks of course).
But hey, if you really believe that players who level learn a whole lot about performance and solid playstyle, and the ability to quest meets your skill requirements for grouping with people, more power to you