The Lord of the Rings and other books by Tolkien are fairly well scattered with references to "It seems that it was meant to be" type remarks and some explicit prophesies such as those by Mandos or Malbeth the Seer. Do these amount to predestination, bringing its notable moral side-effects? - I believe not.

Tolkien was too good a Catholic to adhere to a philosophy of predestination. The trouble with predestination, as Catholic dogma has recognised for many centuries, is that it denies individual morality. For example, if Judas was predestined to betray Jesus then he cannot be held morally responsible for his actions. However, if Judas had "Free Will" and chose to do evil then he is completely morally culpable.

So I believe that Tolkien would have denied the existence of predestination in his works to the extent that each character had the freedom to act at any occasion in any way he chose. However, I think that he would have supported the assertion that the general flow of events was influenced by a higher power.