White Labs #7 is a good yeast. It comes in liquid vials. I used it a number of times and I think it flocculates a little better than #9. It definitely has a different flavor profile. Much more banana-y.
I'm not sure what TMAK means, in regards to #7, by
I'm also not sure if the cider yeast is good for sake.
Maybe you could do a big yeast starter of whatever sake yeast you get. Then you could use your centrifuge to make a yeast cake, decant the wort off, scoop the yeast out and place it in ziplocks / cold storage for later use
That's kind of what they do at Sake One.