My first GSD was a young adult female, picked up off the streets of Boston by animal control. I saw her by lucky accident. She was picked up on a Saturday when the shelter was closed, so they parked her upstairs in our vet clinic until Monday. She was a bicolor GSD maybe 1, 1.5 yrs old, weighing 29 lbs and suffering from mange and a variety of parasites. She was too skinny and ugly to be adoptable, and would be euthanized on Monday. I couldn’t bear it that she’d be killed for being skinny and sick, so I adopted her as soon as the shelter opened. Everyone I worked with thought I was crazy, but all she needed was food, basic vet care for the parasites, and a safe home. Within a few months she was the prettiest little girl, 53 lbs of love and fun. She was house-broken in 3 days, learned in 1 go to Be Nice on cue when taking a treat, and soon she responded to basic commands and I had enough control of her to go anywhere on a leash. She had her quirks, but she was a loving and fiercely loyal companion for 13.5 years and I miss her still all these years later.
So yes, a rescue can bond with you, and be every bit as loyal and loving and trainable as a puppy you raise.