The concept of Creative Confidence" was originally defined by David Kelley. Kelly is the founder of IDEO and the visionary around the development of Design Thinking .
Working with Stanford's d.school, he has been instrumental with introducing this concept to the learning community, one outcome being the School Retool program that we are using here in Oregon.
Here is David Kelley giving a TED talk about Creative Confidence:
Others speak of this concept as Creative Courage.