Just moved him to a 2x2x4 cage this weekend and he looks like he is doing well.
I intend on having him outside on weekends for a while but I think that there are too many birds to let him just sit in a tree or something. I even kept a close eye while he was out in the cage.
I wouldn't leave him unsupervised while outside unless he was in a cage.
They are like little ninjas, they wait for you to break eye contact and then start moving.
We tend to have a good amount of large Crows, Hawks, Gulls, Raccoon's, or Rats in socal as well, as soon as you disappear they could make a very expensive snack out of your little buddy.
I have a local hawk that totally ruins some sunning sessions. I am sure he is waiting for the day I leave him unsupervised.