As I understand it it’s not capped... They can now just capture all the leakage.
The device they just put on can, in fact, have all of it’s connections sealed. They plan to do that tomorrow, and then monitor the pressure.
If the pressure increases to what they expect, they will have in fact stopped the leak and they will be “done”, alhtough they will still use mud to shut down the well.
If the pressure does not increase as much as they expect, that will indicate that there are leaks in the well. In that case, rather than taking the chance of the well being further compromised, they will open up the connections again, and then connect collection risers to process the oil until they cna do the relief well bottom kill.