I am picking up a new German Shepherd male puppy middle of July and would like to know if crates are a good thing to use. I am just a bit worried that it may make him defensive in it. Am I right to worry?

It depends on the way you use a crate whether it is a good thing or not .
If you want a den for your pup where he can go for peace and quiet it is great . Also if you want to travel in the car , or if you show they are also great :)
If you want to keep pup enclosed most of the day ( as some people have indeed used them for ) then no they are not a good thing
We have ours in the lounge and the door is left open all day long and pup also has his toys in there too . The door is never closed on it . Sometimes he may not bother with it for days , other times he likes to go in and sleep in peace :)
Lel