Even if it knows that it must play the move with the highest odds of winning, as far as it knows when it starts considering, that could be any of the moves.

But yes that would be knowledge that its move is objectively deterministic. This would not necessarily prevent it from feeling like it could make any move it wanted, just like people who believe themselves subject to deterministic physics still feel like they can do whatever they want.

But the chess computer doesn't have to know what is determining its moves, in which case it will be even more likely to feel that it can make whatever move it wants.