Horace Horsecollar is correct, Bill Peet was not one of the group commonly known as "The Nine Old Men," but, he did work for a number of years for Disney.
If one wants to see what it was like working for Disney, then read his autobiography, "Bill Peet : an Autobiography." One of the things he mentions, is that not all the employees working for Disney were fond of Mr. Disney.
Enjoy!