Your tort will push a ball around, but it won't be playing with it. If anything, the tort will think it's another tort that needs to removed and is trying to remove it.
Torts don't play. Enrichment for a tort is providing a habitat where it can graze, browse and hide naturally.
I think this is the point. WE enjoy THEM. Not so much the other way around. Just make sure all of his environmental and health needs are met, and then watch him, talk to him and enjoy him in whatever ways suit you. That is the idea behind a "pet".
You can try to put a ball in there and see what he does with it.