Yes, Macbeth has a choice. Even if the witches are messing with his head, he still can choose to ignore the so-called signs. He latched onto those prophecies immediately, as opposed to Banquo who felt disturbed by his. Macbeth could have walked away. He didn't.
More on this topic here: Does Macbeth Have Free Will
Traditional views on tragedy are that he was doomed. Fate always plays a huge roll in a tragic hero's downfall. This is especially true in the original tragedies, like the Oedipus Trilogy.
Macbeth is responsible for his hubris, or tragic flaw, excessive pride.