I seem to recall some debunking of the gains of a A-9 on this forum for many years and backed up by many sources.
No doubt it flew and fought, but as compared to an A-8? Not much difference.
Heh, a quick search yielded this thread from early 2003 discussing the very same plane:
http://bbs.hitechcreations.com/smf/index.php/topic,80177.msg778906.html#msg778906Some go back even earlier!
While it was supposed to have the wide wooden blades, most were made with the standard metal prop blades. While they started with a 14-blade cooling fan, this was reverted back to 12 very quickly.
Essentially the difference was in minor variations in armor thickness, the engine, and the canopy being a bit more bulged. The wings' leading edges were not armored, so much as I think that stems from armor around the ammo boxes on the outboard guns. You find similar armor setups on the A-8 Sturm craft.
Also please keep in mind our A-8 (overweight as it is) does about 408mph. The A-9 is touted as doing a whopping 418mph.
10mph difference, for the exact same plane with more armor weight. It would not change anything in the game. You want fast, you still have to fly a Dora.

P.S. I denounce the "lighter than an A-8" comment because it carried thicker armor plating, by definition having "heavier" armor. Plane for plane, it should be heavier. Now, compared to OUR A-8, perhaps it would be slightly lighter, but our A-8 needs to lose several hundred pounds of false weight to be historically correct.