Here's a copy/paste from a post I made earlier this morning. We had a 8:30 pm ressie and the park closed at 9 pm.
I just wanted to encourage you that dinner is really nice, too. On our last trip we did a late dinner ressie on our last night at WDW.
It was the most magical part of any vacation we have ever had. When we came out the park was EMPTY. There was music playing. The castle was lit up with different colors because of the "goodnight kiss" (or whatever they call it). We took our time on the way out. Took pics of the kids all over Main Street and video of our DDs dancing in front of the castle.
I'm sure my description doesn't sound as "magical" as it was. Also, my DDs and DS2 love the mice from the Cinderella movies, so they were thrilled to see them and get their pics with them.
Keep trying for breakfast, but make the best of dinner if you don't get it. Our dinner experience was so beautiful, my DH wants to end every WDW trip that way. (And he's not the magical type. )