If that was the challenge, then job done. I’ve not watched the video yet to know the precise challenge, but the lesson seemed to be chords in a key, so I made an assumption.
Sorry, I said Dadd9 when I should have said Dadd4. I misread on my phone screen.
I have no idea what fingering you are using, so I’m not sure what the proper chord name is. You may be thinking of a Dsus4, perhaps, which is similar fingering, but as soon as you add the F# in the bass note, it’s no longer a sus chord as the F# provides the 3rd of the chord.
The following thread discusses this:
To be honest, this is getting quite a way above where I think your level is currently, so I wouldn’t worry about it. From a theory point of view I would stick to major and minor chords and understanding them first, as they are more fundamental. The “sus” and “add” chords come into “altered” chords which is more advanced, and is probably best tackled when you have the basics under your belt.
Which is, kind of, why I posted a warning above.
Cheers,
Keith