According to Reuters sources

It is said that the waiver granted will only last for 180 days and China will have to disclose the counter-parties that they deal with as well as settlement methods. For some context, August data showed that China imports roughly around 800k bpd of Iranian crude so this constitutes to about 45% of that.

There's no certainty just yet if China will stick to the capped amount but the headlines will mean that there should be less supply of Iranian crude in the market at least. But again, how this works in practice remains to be seen.

WTI still trades at around 7-month lows today, sitting a little lower at $62.84 currently: