Also 30 minutes in one go is a bit too long - they can get stressed in the ball if in it too long. I would say 15 minutes maximum. You can give him another 15 minutes after a break. Or if you have a bath (dry with plug in - no water) you could gently put the ball down in the bath after 15 minutes and take the top off and let him run around in the bath with a couple of toys in there (eg a kitchen roll inner tube or a mug on its side - something to hide in). It can be a good way of taming them so they get used to being handled as they can run around but not escape.
This is what we did - with advice from the forum. Sometimes you can get in the bath as well - get in first then take the lid off the ball - and let them run all over you. Second person needed nearby to use an arm as a guard in case they run up to your shoulder and try and jump out. It helps to get them used to you and your scent so they start to get tamer and accept you.
In 6 months time he'll probably be sitting between you on the sofa
I would upgrade the cage as soon as you can though - this might set taming back a bit but it'll soon get up to speed again and he'll be happier and more settled in a more spacious cage - you can almost see them smile. Our hammy was terrified for the first 10 days (it can take 2 weeks for them to adjust after a cage change) but after that he was happy as larry and chilling out.
https://www.youtube.com/watch?v=kjyEme2xcq4