Daytime routine for pup

Hi all, just recently adopted a Labrador mix puppy. He’s sweet as can be. Seems to have some separation anxiety. Finally got him comfortable with his collar. I drive a bus AM and PM and work near my home during the day. Normal routine is wake up at 4:55 I take him out of his crate and take him out to do his duties for 5-10 minutes. I leave at 5:30 during which he is recrated and fed. I return at about 8:00 and play with him til 8:15 in which I have to be at work. I let him outside tied to a 40 ft lead during the day, there’s shade available and I’m normally within 200-400 ft from him. And I go in for lunch at 1:45 he comes in with me. I eat lunch and play with him for a few minutes and recrate and feed him a small snack for lunch. And I leave around 2:15 for my evening run. I normally return at 6 or so. He howls all day while he is tied outside. Will he get used to this or do I need to limit his time outside and recrate him? Or will he need to get used to being outside? Can’t let him roam around the entire house just yet as he’ll get into things. Just wanting to make sure I’m doing this right.