Cleared Planet 7 while giving that crystal another spin. 354 frames saved over my last attempt. I also collect the money necessary for my shopping, with plenty to spare.
With the way I handled getting through with a tethered crystal, I'm now constrained by how quickly I can give that crystal a whirl. I held on to it up until I get to that large wormhole with the Golden Ship Part.
Planet 8 is just a quick warp to Planet 13. I shouldn't have too much trouble getting to Planet 12 at this point. I'm given the impression that this game is pretty sync-stable, with the only thing to worry about is future RNG. Using player 2 can deal with any RNG related mess.
... I seemed to have gotten back to this one. Sorry for those who expected more Soul Blazer.