We've done Tusker house 2 times, both between 8:30 & 9:00. The character interaction was fabulous, Mickey, Daisy, Goofy and "The Donald" stayed a good amount of time at each table, dancing and taking pictures. It's the best character breakfast at WDW, we've done them all. It's also very close to the Kilemanjaro Safari, easy to get Fast Pass while having breakfast. We did Kahli Rapids right after that, big mistake!
The buffet is wonderfully fresh, with typical breakfast foods along with some African ones as well. We've enjoyed it both times. P.S. The kids loved it too!