chris> Is there any possibility to install NetBSD with Mac OS 9 on the same 
chris> disk, without erasing the whole disk.

I belive by using disklabel (-e wd0) , you can do that, while I am not sure.
(looks self-contradiction..)

What does it look like if you run disklabel wd0 at install kernel ?
My iBook says ( although this is not at install kernel)

#        size   offset  fstype [fsize bsize   cpg]
 a:  1024000     1544  4.2BSD      0     0     0 # (Cyl.    1*- 1085*)
 b:   593920  1025544    swap                    # (Cyl. 1085*- 1713*)
 c: 11733120        0  unused      0     0       # (Cyl.    0 - 12415)
 d:      200      320 unknown                    # (Cyl.    0*- 0*)
 e:  3686400  2643464  4.2BSD      0     0     0 # (Cyl. 2797*- 6698*)
 f:  3276800  6329864  4.2BSD      0     0     0 # (Cyl. 6698*- 10165*)
 g:  1024000  1619464  4.2BSD      0     0     0 # (Cyl. 1713*- 2797*)
 h:  1024000  9606664  4.2BSD      0     0     0 # (Cyl. 10165*- 11249*)
 i:  1036910 10630664     HFS                    # (Cyl. 11249*- 12346*)
 j:    65536 11667574     HFS                    # (Cyl. 12346*- 12415*)
 k:       10 11733110 unknown                    # (Cyl. 12415*- 12415)

i and j are MacOS bootable partition,

If your disklabel fails, there may be another way with bootable
CD-ROM, suggested by Y.Takizawa, see
http://www.netbsd.org/cgi-bin/query-pr-single.pl?number=11513
---
(Makoto Fujiwar)