Hi, Charlie -
From your first post -
I tried to install OS9 from an install disc but it won't install because there is no Classic system folder to install to.
From your most recent one -
"Classic cannot find a Mac OS 9 System folder on the startup disk to use."
The meaning of the message given in the second is not what you inferred i8n the first, which is why it is important to use the exact wording of the message received.
Your machine is booting to OSX, not to the OS 9 Install CD. The OS 9 installer app can not run in OSX. When you try to do so, OSX looks for an install of Classic in order to start it up so that the installer app can be run in Classic - this is the normal response of OSX when an OS 9-only app is initiated. It fails to find Classic, and so returns the message given in your recent post.
The solution is to boot the machine to the OS 9 Install CD; once booted to OS 9 on the CD, the installer app will run. Your machine apparently fails to do so. This could be caused by several reasons -
• The OS 9 Install CD is a model-specific one for a machine model other than the G4 (AGP) model which you have. Model-specific OS 9 disks have a gray or blue-gray label, and state a model designation on the label in addition to the name "Software Install". Retail OS 9 Install CDs have a white label with a large gold 9 on them, and are capable of booting and installing to any Mac model supported by Apple for that OS version.
• The OS 9 Install CD is a retail one, but one of inadequate version. The early G4 (AGP) models came with OS 8.6; later (near end of run) G4 (AGP) models came with OS 9.0.4. If yours is a late model G4 (AGP), it may not be able to use a retail OS 9.0 Install CD - so, if that is what you have, that may be the issue.
• Some folk have reported that the latest firmware update released by Apple altered the firmware such that the original OS version (the one that came with it) can no longer be used for booting. In this instance a retail OS 9.1 or 9.2.1 Install CD will still work.
***
If the OS 9 Install CD that you have is not a retail one, or is not at least for OS 9.1, you should acquire either a retail OS 9.1 or OS 9.2.1 Install CD. This meshes with the requirements of OSX, that an OS 9 install intended to be used as Classic must be at least version OS 9.1. Given that some folk have found that OSX 10.4 seems to prefer OS 9.2.1 or 9.2.2 (the latter has no retail version available) and does not always work well with OS 9.1, suggest you acquire a retail OS 9.2.1 Install CD. The best price for such seems to be from Apple - although it is no longer available from the Apple Store, it can be got via telephone order from Apple's Customer Support -
http://www.apple.com/support/contact/phone_contacts.html
***
I have no OS 9 drivers installed. There is no System Folder because that is part of OS 9. There is nothing on my hard drive that has anything related to OS 9.
If you do not in fact have OS 9 drivers installed on the hard drive (they would be in an invisible partition of the drive, and are not part of an OS 9 System Folder), then you will not be able to install OS 9 directly. In the absence of the OS 9 drivers, no OS 9, including that on an OS 9 Install CD, can mount the drive; and with the drive not mounted, the OS 9 installer app can not 'see' the drive, hence can not install onto it. Since the OS 9 drivers are not visible, if you have not yet checked for them via System Profiler, do so.
If they are not there now, it may be possible to recover from that relatively painlessly, provided that the OS 9 drivers had once been installed on that drive. See the part about using Drive Setup in this Apple KBase article -
Article #TA20774 - Disk Is Available in Mac OS X But Not in Mac OS 9
If all you need OS 9 for is to use it as Classic, and will not need to be able to boot the machine to OS 9, then there is an alternative - copy a working (bootable) OS 9 System Folder of adequate version (ideally OS 9.2.1 or OS 9.2.2) from another Mac. This should work fine as Classic, but unless the machine it is copied from is the same model as yours, it will not be able to boot it. Note that an OS 9 System Folder can be copied via a Finder copy process (drag and drop), and it will be usable; it is not necessary to use a cloning utility with OS 9.