Assuming for a moment that the test websites didn't give a specific reason to trust them more or less than any other website operator. This means that if your website has significantly more than those 9% consent, you're either perceived as very trustworthy, or your GDPR banner is confusing (or, less charitably, deceiving) users.

Would be interesting to see how the consent rates for big offenders like techcrunch, newspapers etc are. IIRC there were specific studies about which brands are trusted by consumers, and Comcast et al. didn't fare all that well in those.