I wonder if there is a way to display a chord as Emin7/9 or E-7/9 or Cmaj7/9.
I tried, but for me i tis either E-9 or E-7, it seems to be impossible to have both or even more extensions. It would be great to have that option. Cheers R

Normally Emin9 is taken to imply the 7th, likewise Cmaj9. There’s no need to specify it - unless you have a particular use case in mind?

Maybe you could enter it as text. “m7/9” sounds like a non-standard chord name to me.

It’s pretty nonstandard so Dorico doesn’t really provide an option to automate this. I’m not sure why you wouldn’t just use Em9, but if you really want to do it, you can modify them individually in Engrave.

Not exactly what you asked for, but you can get this result if you enter the chord as Emin7add9, and remove the “add” with this setting.

You can have multiple extensions if you append them to the end, e.g. add9add11addb13