9vx crashes on me quite often, and qemu doesn't. That's the only reason I use qemu, otherwise I'd also be stuck with 9vx too :-)
Are you running the latest from sources, or are you using the prebuilt binary? There are important stability fixes in the sources that aren't in the binary (unless its been updated recently).
Hugo
Tim Newsham | www.thenewsh.com/~newsham | thenewsh.blogspot.com