A lot of us have the obsessive habit of making ADRs as soon as the 180-day window opens, or as soon as we book.
Or
before we book

--we were planning on mid-August, hoping for free
ddp then, and made 2 weeks worth of ADR's. Once the dates became fairly certain (and didn't include early August

), we decided kind of last minute to try for late September. But I wanted to make sure I'd be able to get all the ADR's I wanted, so I (and many others, I'm sure) made all of them the weekend
before the free ddp booking window opened.
To the OP: If you want Le Cellier for dinner, you may already be too late. I'm hearing they're completely booked up for dinners for September. Most other places you should still be able to get into, if you're flexible with your times and if you book
soon.
As for recommendations, I'd urge you to try a variety of different types of restaurants (popular choices in parentheses). Try the buffets (Boma), the character meals (Chef Mickey's), the family style places ('Ohana), the classics TS restaurants (Le Cellier). Eat in the parks (esp at World Showcase in Epcot), at resorts (Kona), at DTD (Wolfgang Puck's). Eat at some places for the unique atmosphere (Coral Reef, Sci-Fi), at others for the unique "personalities" of the CM's (Whispering Canyon Cafe, 50's Prime Time Cafe), and at others for that one thing you can't get anywhere else (twin lobster tails at Cap'n Jacks).
And don't worry--2 adults won't feel out of place anywhere, so if someplace sounds good to you, go for it. Have fun planning!