Hello,
> I upgrade my mail/clamav installation to 0.9 (on NetBSD 
> 4.0_BETA/sparc64) and the clamscan seems to core very often.
I had similar issues on sparc Solaris10.
In my case it happens when scaning excel files with clamav 0.90.

Either comment out --enable-experimental or look at bug #329 at
https://wwws.clamav.net/bugzilla/show_bug.cgi?id=329

There is a patch I got from the clamav developers which resolved my 
problems.

Regards,
Uwe