OS9 (Classic) should be considered (loosely) a hardware based OS - this means that drivers ENABLED hardware. OSX (10) should be considered (again loosely) a software based OS - this means devices work by standards and all devices are just abstractions of each other.

Why did I tell you that? Because OS9 compatibility for the ethernet adapter like I sell is really dependent on the extent of the damage done to your ethernet controller. (Is the chip on the logic board fried or just the port connection?) But the other factor is - what ethernet controller did Apple use on your particular Mac? On the iMac rev a-d - Apple used 9 different manufacturers of ethernet controllers - it isn't possible to find out which chipset they used on each Mac - especially if fried. My USB to ethernet adapter is only compatible with zylinx chips of a certain run = 8503. Becuase of the weird way in which OS9 handled TCP/IP data - this is the only chipset that supported Apple products - my adapter has to be a MATCH for the hardware in OS9 ... it can be an abstraction in OSX and that abstraction can be done though software. My adapter ONLY works if it matches your chipset (8503 zylinx) AND your chip is not damaged at all AND if you have 9.2.2 applied with ALL updates.

That being said ... there is ONE adapter that was specifically commisioned by Apple of Jaton Inc - that works universally. This adapter has not been made for 7 years. A company called Broadband Products carries a few in inventory, but they only sell to whole salers. I have 3 of these adapters in stock - I can set a private auction up for you for $40.00 and sell you one of these OR you can take a risk and see if the Farallon adapter I could send you will work. I will warrant the $40.00 adapter to work and we can sort any problems out by phone. I cannot warrant the Farallon adapter for you - well I can - but only for OSX 10.3 and higher!