Its a common question- from coaches, guidance counselors, teachers…
What is the correct answer? What should go on the college resume?
A- highest composite score from one test date
B- Superscore
C- Something else
On the one hand, I think B. The vast majority of schools claim to only consider superscores, so in effect it is your score. But…
I feel the nagging obligation to qualify the answer as “she got an X, superscored”
First choice is decide if you need a ‘college’ resume…many, probably most students don’t.
As far as how to report, there’s usually room for both scores. ACT 30, superscore 32. It’s entirely appropriate to share superscored results because as you say, most schools accept that (and it’s what they report in their CDS/IPEDs data). I think it’s ok to also just say ACT 32 unless the resume is going to a non-superscoring school. So, not sure my answer helps at all 
I think when you report to schools, you fill in the spaces available- if it leaves lines for multiple test dates, you provide all info. If they ask for highest, you provide highest.
But beyond actual applications, when speaking to a coach for example- do you go with A, B or C. Is it a different answer when speaking with an admissions officer?
If self-reporting, the common app has students report their highest composite score and highest scores in each section. For official scores, ACT’s report is now a superscored report, I don’t think CB does that yet for SAT. I don’t know any school besides Georgetown that requires all scores, although a few do prefer all.
I would have the student say ACT 30, 32 superscore, to coach or AO, presuming the school superscores. Which the student should have already researched.