When you say "eat outside", do you mean eat at one of the table on the patio or in the sunroom? Those are like any other table at Tutto Italia, so yes, I would make an ADR if you know you want to eat there. As far as I know, they do not "hold" any of the tables for walk-ups. If they aren't booked solid, then they'll take walk-ups. You can probably request a patio table when you check-in, but you can't request it in advance.