The 7200 is more neutral in tonal response, especially in the bass.
To my ears, the P9's bass got very easily bloated with some modern and most electronic music.
The 7200 on the other hand was more versatile and forgiving.
Neither of them possess a 'large' soundstage, and the 7200's soundstage is fairly small and 'in the middle of your head', especially for it's size.
7200 is easily the more comfortable, and one of the more comfortable headphones around generally.
In my opinion, the P9 was trying to do something unique and special and 'fun' with it's sound, but in doing so, made a lot of people really hate it.
7200 is trying to be safe and in the middle of the road. I don't think anyone could ever hate it. But I didn't love it either. Kinda boring.
If it's any consolation, the AH-D7200 has about 90-95% of the AH-D9200 DNA, which was only a touch more airy and detailed in the treble area.