Well assuming time travel is within the laws of physics then free will is 100% certain.
If time travel is not possible in any shape or form,then NO free will is just based on previous events,so while you feel free to do what you want now once its been done it cannot be undone,so from your point of view your future situations are based on your past ones,you can make choices but many are thermodynamically impossible to reverse,some of which you had no choice but to do,like living which is a thermodynamic process,once you were born youre pushed into the thermodynamic second law which you had no choice about,now the future is just based on that.