I use new 8x57 RP brass for my 9.3x57. I suspect any of it would work. I've used 30/06 brass but unfortunately, the '06 brass needs to be outside neck turned to fit my 'tight' necked chamber.
I've had good luck with 8x57 brass and see absolutely no reason to change brass. If you wanted to, you could probably even re-stamp the 8 into a 9 with machinist stamps. Use an internal fitting rod, maybe 3/8" diameter held in a bench vice to hold the case for stamping. I don't bother, but this is what I do to prepare my brass.

I neck it up straight, then down in a FL die until they 'just' chamber with a crush fit on closing the bolt. that was, the brass fits perfectly in a chamber that is too long, as my 9.xx57 chamber proved to be.

Dies used for necking 8x57 brass straight- only one or the other- single pass - no case loss - inside lubed with Imperial or STOS

here's the brass.
1/.- 8x57 RP case- new
2/.- 8x57 RP case simply necked to hold the 9.3mm bullet
3/. 8x57 case necked straight
4/. 8x57 case necked straigth, necked to hold a 9.3mm bullet and at a height to make a crush fit perfectly fitted to my chamber. Note the height of the neck compared to #2/. That visual difference, readily apparent is a mere .019", but shows excessive headspace that would cause stretching at the web and early case failure if simply necked and fireformed using 8x57 cases without the straightening & re-necking process. I prefer my brass to last indefinitely- thus, straight first, then necked to fit.

The same process using the same necking up die for making .375/06IMp or 9.3x62 brass from .30/06 or .35 Whelen cases.