You know, the whole "higher power" thing never really made sense to me. When Crayak was kicked out of his galaxy or whatever, he was still a more-or-less mortal (or at least physical) creature. That's how he was when the Ellimist met him, right? Granted he had his own planet (was his own planet?), but at that point he was not yet a nearly-omnipotent being that existed beyond the fabric of space-time. Either the force that kicked him out was made up of nearly-omnipotent beings that existed beyond the fabric of space-time (in which case, why didn't Crayak ever try to copy their example?) or Crayak has now become more powerful than the "higher powers" that originally kicked him out. Food for thought.
As far as the living planet issue goes, I don't think so. Not that I think it's implausible (Father was pretty much a living planet), but rather because of how he's described when he decides to take physical form. A melding of biological and mechanical parts with a giant red eye. It seems to me that Crayak probably started off as a biological creature that incorporated machines into his own structure to make himself more powerful, basically turning into a living spaceship like the Ellimist did (probably for different reasons, though). And the 'planetoid' that is described in the Ellimist chronicles sounds more like an extension of this body/ship, rather than his original form. Sorta like the Death Star, I guess.