For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.
Just don't. Save the chips for the board that need them as 9000 chips are nowhere to be found either.
All 512MB 0005 boards you can just slap a 9000 on there and it should work. On 1GB board you will need to change the VRAM chips so fuck that.
I have no idea. Compare strapping resistors between 9000 and 005 boards. R8613 and friends. I think 0809000 is only properly supported in the early 2011 BIOS so you can only downgrade early 2011 models.