I agree with the previous posts - all baby balls are different. I've had many That are just as defensive and prone to Strike as my BRB's but often times they're ferocious feeders as the last person said. I currently have a YB, spider and super Mojave that are just crazy! As soon as I open the cage to clean, they'll come striking out of their hide, tag me a couple times and then retreat in that half in/half out S pattern you mentioned. It's nothing to worry about and it's actually kind of cute. They usually always tame down with age and out of my collection, there's only two adult balls that never did and they arent even that bad - just a little cage defensive.
Usually once they're out, they settle down but what you mentioned about if you leave them be when they're out and then go to handle or approach them and they become defensive again - well that's completely normal as well.
Be confident and If you think you're going to jerk back if you get bitten then wear gloves or use a snake hook. Jerking away when they bite can hurt the snake, especially if it's young so keep that in mind. Handle regularly but don't overhandle.
All the best!!