Try them both and see which one you like best. It really matters not at all to the Amiga.
However, as you used "color" then I presume that you might well be based around NTSC standards (which has white as 240,240,240) so you might prefer it brightened up a bit at 9300K. If you had used "colour" then I would have presumed PAL standards (with white as 255,255,255) and 6500K might be fine to your eyes.
I'm using a 6500K white point right now on my PC monitor - but at 100Hz refresh, it looks brighter than it would at lower screen rates.
