Pretty much, the WS eateries close at 9 (though I'm not sure about the ones which require a PS, but I would think if you were trying to take advantage of the late hours you wouldn't want to waste that much time anoyhow.) Among the quick eateries: the Japanese one gets low on food near nine, the American eatery took forever(as in slow), the German eatery was great - it's a little bit hidden and had a very short line (if you like bratwurst and chocolate cake), the Mexican pavillion's eatery seemed to be open the latest, they were still open after the fireworks - but I think only for people who were already in line. I don't know about the future world eateries, but since much of future world closes at 7, I doubt they are open late.
On the other hand, I don't know when exactly you are arriving - we had a great meal at the Yachtsman's Club that wasn't too expensive for a sit -down meal. It wasn't very crowded either - the steak sandwich was excellent! You could also grab a slice of pizza at the Boardwalk to eat on the go.
Last, keep in mind that unless they change things - you'll have to walk all the way around to where the WS meets Future World to get your bracelets for the extra hours- and you can't send someone ahead to get them - everyone has to go in person and show a room key.
So maybe Mexico before 9 or pizza on the Boardwalk would be your best option.
One of the drawbacks we discovered to the late hours was a lack of eateries. Maybe Disney will change this - it seems like a major snafu on Disney's part not to want to take advantage of the opportunity to make more money off of people. We were often hungry when we got back to our rooms after the EMH's. Having a fridge in our room really helped. We kept cereal and milk in our room, and we also made a habit of getting snacks like German pretzels, or pastries or cookies early in the evening when we weren't hungry to eat later when we were hungry. I think maybe YC does have late night room service, but the mod hotels don't. (only until 11p.m.)
