I would agree that there is the undeniable undertone of predestination in the book. Clearly, there is some higher power that sets events in motion. It is, however, the individual character's choices that influence which direction these events will take. Thus, Frodo is "meant" to inherit the Ring and "meant" to undertake the daunting task of destroying. But he must make the choice to do so. Gandalf does not tell him that he must do it; he guides his decision, but in the end it is Frodo's decision solely.