Well it seems like you installed 6.5's in your rear deck.
not 6x9's.
Use the edit button.
Mine fit just fine.
I have the entire plastic retainer with my aftermarket 6x9 out of the car.
Lemme take a picture....
Edit:
The plastic stuff there is one of those "bass boomers".
I put them in to see how'd they work.... not well. turns out 6x9's love oversized enclosures (aka your entire trunk) so i cut it open and tore most of it off.
Took less time than pulling the rear seats out.