Thanks for the swift reply. The console says Fail to load fselect.flt.
OK, that confirms the modules aren't loading.
Modules (including fselect.flt) should be in the CHDK/MODULES directory on the large partition. If they aren't there, something went wrong in the install. You could manually copy them, but they should be from the same build as the DISKBOOT.BIN that's was installed on the small partition. It might be better to format the card and start over.
If the modules are there, either the firmware isn't looking at the right partition (which seems to be contradicted by the Canon UI showing many shots available) or something else is preventing CHDK from seeing or opening the files.
Possible causes of CHDK not being able to access the files are maybe filesystem corruption, presence of other files with "weird" (not basic 8.3 with letters, numbers _ etc) names, or a bug in this CHDK port. None of these seem very likely, but for the first two, format and start over would be the thing to do.
Which Canon firmware version does your G9 have?
The Canon OSD says thousands of photos, so it sees the large partition.
Just to confirm, this was checked with CHDK running?