Tidus does come back physically.

Spoiler Alert!
There is once scene in X-2 where Yuna falls into the Farplane. As you walk her around the vast darkness whilst mashing the X button (O button for the Japanese version), Bahamut's Fayth will appear and will ask a question about you wanting Tidus to come back or not. You are given two choices both of which you want him back badly or it's better this way without him. Regardless of the percentage you get during the game, Tidus will still appear if you choose so.