Want to install an older version of OS X.

that model identifier spans three iMacs.

according to Mactracker, if yours is an iMac (17inch Flat Panel 1GHz) , the oldest possible OS X that it can run is OS X 10.2.3.

and if it either the 17 inch (USB 2.0). or the 15 inch (USB 2.0) then the oldest OS X that it can run is 10.2.7. so if you need an earlier version of macOS for your workflow, you would actually need an older machine.

but if any of the above OS X will suffice, then you can search eBay or elsewhere for in install DVD for that OS. one example would be Apple OS X 10.2 Jaguar FULL INSTALL - 2 CD-ROM Set. that seller shows that he has a 100% positive rating. but you might want to research there for a better price.

since you don't know which disc came with your Mac, I'm guessing that you no longer have it, as it is the disc that was included in the box when it was first purchased.

given that, first, you can open the apple menu. and then with it open, press and hold your keyboard's "option" key. "About this Mac" will change to "System Information". click "System Information".

and then look in "Hardware Overview" and determine the mac's "Model Identifier".

with that info, we should be able to help you with which installation discs will work for your Mac.

likely you will need the OS X install disc that came with the Mac. you may also be able to source an OS X installation CD from eBay or somewhere else. but I personally be reluctant to take that route, because you cannot know for sure that the disc does not contain any PUPs.

have you started by inserting the first disc, and then restarting the machine? and once it begins to start up, holding your keyboard's "option" key until "install OS X" shows up on your screen?

if those are not the steps you are trying, what are you trying?

and as far as emulators and such to run an unsupported OS X (macOS 9) the only thing we can say here is "google it". and even that is bumping against the edge of the terms of use of this community. we are not allowed to help with violations of apple's macOS user license agreement. and an emulator lands directly there. sorry.

panics are usually indicative of a hardware issue. and with a 20+ year old Mac, it is possible that your HDD is operating in a state of failure.

but my knowledge of such an old iMac, as well as such old versions of OS X is extremely limited. so I have posted this discussion in the lounge, and eventually I'm sure that someone with knowledge of your Mac and OS X versions will see it, and hopefully they will be able to give you more assistance.

Are you suggesting that I can get a Classic emulator that's a "stand-alone" program, and not a part of one OS X version or another? Then, I could just install it on whatever version of OS X that I was running?

Yes exactly.

As you say you might need an emulator. So I suggest you search the net for one. There is one that runs OS9 and I am told it will even work on an M1 running sequoia.