I came upon three B89 interviews courtesy of 1989Batman's YT channel.
Keaton Interview. He talks a little bit about 60s TV show as well.
Sam Hamm interview back upon B89's release.
Bob Kane interview.
It's sad that he doen't even mention Bill Finger. Who's really responsible for the creation of Batman. Throughout the short interview Kane says stuff like "my creation". And has the nerve to say that "when he's a 120 years old that WB and Leonardo could send him the residuals and he'll invest with the angels." Too bad he never considered investing with Finger.