Maybe. The slot is bigger than what will actually fit depending on how it's installed. Is it a standard double din mounting but then a bigger screen?
I bought this to fill in the gap so the 9 inch might do that better then my ebay plastic piece.
https://www.ebay.com/itm/304411138930
I just did mine last night and it was a mess. Mine is a 98 with the pioneer amp. Can you take pictures of the wiring in the dash and also by the amplifier?
I have an ATOTO in my son's car and I've been happy with it. Especially for the price. WIll the 9 inch fit though, it may be too big...