B flat major 7th add 9 which notes the seven and a 9

Major 7 chords with an added 9 would just be a major 9 chord, so the chord you are looking at is a Bb major 9.

The major 7 note is A
The 9 is C

You can look it up here to find all the notes, just select the Bb major 9 chord to get the notes.

https://www.guitar-chords.org.uk/chord-calc/chord-note-finder.php