No, Ocarina of Time was not an open world Zelda game. It was “open zone,” if that, and was only non-linear in like, two places. Only some of the temples as Adult Link could be completed in a different order thank intended. Ocarina of Time is a linear game, with a curated experience. You more or less accomplish a task that unlocks the next place you need to go. Sure, you could technically go to the front door of some areas despite you never needing to, but doing so was pointless because it was just a barrier until you completed the necessary task to unlock it. The order of those places getting unlocked is more or less the same for every playthrough.

This is different from the other open world Zelda game, where going somewhere is technically never pointless, because your can always access everything from any point in the game (making Quest Items meaningless, which is likely why they were removed from those games).