LIGO observations are very well explained by the merging of two black holes, and there is so far no alternative hypothesis that explains the detected gravitational waves as good.

However, you are right and this only consists of an indirect probe. Concerning direct observation, we are far from being there. The Chandra observatory collected a bunch of data a couple of years ago. The EHT telescope that combines the strengths of several existing observatories gives good hopes to learn more in the future.

If you allow me, I would add this reference to your post, so that other readers could find more information.