The 6/9 is also named sixth/ninth
Use 69 instead of 6/9
Use M69 instead of 6/9
A 6/9 is a Major chord
How to construct a 6/9 chord?
Use the following intervals in any order to construct this chord. Start on a specific note on which you want to construct this chord from (for instance the note "C") and calculate each interval on top of it. Afterwards, you will be able to play it on your instrument.