Is it safe to start learning and using Rust for hobby projects or should I wait until 1.0?
How much involvement did he have on the project?
(The "mozilla" people (brson and pcwalton) are the people to listen to there.)
Brendan's resignation as CEO will have no effect on Rust or Servo.
Many people at all levels of the organization are huge supporters of Rust, Servo, and Mozilla Research in general.