Is it possible to reduce a SAT problem to it's simplest form with no assumed variables in P time? So as you read in the title I want to know if it is possible in polynomial time to reduce a SAT problem to it's simplest version in CNF format with no assumed variables?

The simplest form is with minimal gates in the circuit, assumed variable is not important it was assuming the value of a variable.

An example, I have a problem which has only one solution and it is phrased in CNF/SAT but a simpler version in CNF would be a list of conjunct clauses with only one var is it possible to simplify to that.

What if i already know the problem has a solution can simplification run in P time?
No, this is not possible, unless $P=NP$.

Why? The formula $x \wedge\lnot x$, which is always false, is technically in CNF. But, this is unsatisfiable.

Suppose we could do this in polynomial time? Then to check of a problem is satisfiable, we just minimize it. If it minimizes to our false formula, then it's not satisfiable. If it minimizes to anything else, it must be satisfiable! So we've solved SAT in polynomial time.

In terms of gates, we have the same problem: if a formula is UNSAT, then always outputting LOW is the minimal gate circuit that's equivalent.