They were bold enough to surprise the teachers. Admitting creation can not be "proven " but neither can evolution so , both are indeed theories. The is no way to prove neither.
Point of order, but Biblical creation is a belief, evolution is a theory.
No proof is necessary to hold a belief, and no amount of proof can disprove it. It need not be consistent, nor logical, nor credible. It just is.
A theory is a postulation of a set of rules, which can then be dis-proven, and subsequently replaced with another set of proposed rules.
It's impossible to NOT BELIEVE in the theory of evolution. It's a theory, not a belief. A person can try to disprove it scientifically, but I've not seen that done yet.