I need to input an E+7(#9) chord
Which chord to select in the chord builder?

7#9b13 has the right notes but theoretically a plus is not the same as a diminished 13.

Am I overlooking something?

Sorry, I was overlooking something: 7#5#9
The chord builder seems somewhat disordered to me

Much like the sound of a 7#5#9. A coincidence??

If you are asking how to simply enter the chord into BIAB, don't use the plus sign, use #5. And don't use any parentheses. So it looks like this: E7#5#9

There may well be another way, but this is how I do it.

You may also find that E7alt works.

Look at Help-Index-chord then click on chord list. The list of BIAB chords is there.