Hi, chaleena -
Grant's response to your other thread indicated that that is not possible.
No Mac Mini, any model or speed, can boot to OS 9 under any circumstances. This means it can not use OS 9 as an operating system.
All Mac Mini G4 models can use OS 9 as Classic, but when used as Classic it is not an operating system. Classic is an installation of OS 9 that is used as a program while the machine is booted to OSX (OSX is the operating system); in this mode it provides an environment in which many, but not all, OS 9 programs can be run.
The only source from which to install Classic on a Mac Mini is the original disk set that came with the machine.
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If you want a machine that can boot to OS 9.2.x, I would look for a used or reconditioned G4 tower model. All of those except the G4 (MDD) models with a FW800 port can boot to some version of OS 9.2.
Note that the later G4 Quicksilver and all G4 (MDD) models can install OS 9.2.x only from the original disk set that came with them, so if you get one of those be sure to get the original disk set that came with them.
The original G4 Quicksilver models and all earlier G4 models can use a retail OS 9.2.1 Install CD, so do not need their original disk set (though conscientious sellers will still include them).