Board Thread:General Discussion/@comment-43542357-20190818074355/@comment-35564842-20191029083632

Notice anything about Star Platinums original stats?

He has an A in development potential

And now look at his stats after he unlocks time stop

Still an A (at least in part 4)

This means that Star Platinum always could stop time and Jotaro just either didn’t realize he had it or just didn’t use it for whatever reason. Time stop is an inherent ability. Just like Josuke’s healing.