Try the plan9port tar:
$ 9 bunzip2 < plan9.tar.bz2 | 9 tar x
$
> I got crazy permissions here?!
>
> $ tar jxf plan9.tar.bz2
> tar: plan9/mnt/exportfs/16: Cannot mkdir: Permission denied
> tar: plan9/mnt/exportfs/1: Cannot mkdir: Permission denied
> tar: plan9/mnt/exportfs/10: Cannot mkdir: Permission denied
> ...
> tar: plan9/mnt/exportfs/9: Cannot mkdir: Permission denied
> tar: plan9/mnt/cons/cons: Cannot mkdir: Permission denied
> tar: plan9/mnt/cons/consctl: Cannot mkdir: Permission denied
> tar: Ignoring unknown extended header keyword `SCHILY.dev'
> tar: Ignoring unknown extended header keyword `SCHILY.ino'
> tar: Ignoring unknown extended header keyword `SCHILY.nlink'
> tar: Ignoring unknown extended header keyword `SCHILY.dev'
> ...
> tar: Ignoring unknown extended header keyword `SCHILY.nlink'
> tar: Error exit delayed from previous errors
>
>
