If a logic sentence is true but not possibly provable from its construction theory, then it is not preprogrammed ("predetermined") by such system. In mathematics, these logic sentences are termed "Godelian".
Godel's first incompleteness theorem establishes the precise conditions that the construction of the system must satisfy for its corresponding universe ("model") to contain true Godelian sentences.
We also assume that the physical universe satisfies the elusive Theory of Everything, i.e. the otherwise unknown construction theory of the physical universe.
If a person truly has free will, then his impact on the physical universe is a collection of Godelian true logic sentences that cannot be predicted nor proven from the Theory of Everything.
In arithmetic theory, the existence of a Godelian sentence automatically implies the existence of nonstandard universes of natural numbers.
Wikipedia on nonstandard models of arithmetic:
Similarly, if human free will exists, i.e. if there are Godelian sentences in the physical universe, then just like in Arithmetic Theory, it necessarily implies the existence of nonstandard physical universes.In mathematical logic, a non-standard universe ("model") of arithmetic theory is a universe that contains non-standard numbers.
There are several methods that can be used to prove the existence of non-standard models of arithmetic.
From the incompleteness theorems.
Gödel's incompleteness theorems also imply the existence of non-standard models of arithmetic. The incompleteness theorems show that a particular sentence G, the Gödel sentence of Peano arithmetic, is neither provable nor disprovable in Peano arithmetic. By the completeness theorem, this means that G is false in some model of Peano arithmetic. However, G is true in the standard model of arithmetic, and therefore any model in which G is false must be a non-standard model.
Therefore, what religion calls heaven and hell, i.e. the religious multiverse, necessarily coexist with free will. They both exist, or they both do not exist.