Yes, you do need your spouse with you in the car when you leave the garage. Now, you can add him at the kiosk and have him with you when you leave the garage (not sure where you are going to pick him up after he gets the luggage, but, you cannot drive on the lower level). The easiest thing is to have him get the luggage and meet you in the garage if you want to add him to the contract. He needs to be on the contract if he is going to drive the car, even if you are an Insider. Something that was drilled into our heads during training.
From the website: An additional driver may only be added to the contract at a rental location and may be added or removed in the middle of the contract. When adding an additional driver in the middle of the contract both the renter and the additional driver must be present at the location.
Can I add him during online check in and then have him with me on check out? Also can I have him drive the car out of the garage if I make the reservation under my name?