"Agreed. So evolution is still just an unproven theory?"

Non sequitur. Evolution is a theory. It is also a fact. No fact is 100% certain. No fact is unquestionable. This is a false dilemma manufactured by creationists. Nobody has ever seen a hydrogen atom, but we don't insist that their existence be taught as anything other than fact to high school students.

"Especially with the mystery of how an eye would evolve if the organism or animal had never seen light before, right?"
No.

"Or did light sensitive cells just happen with no known need?"
It's not about "need." It's about advantage.