I see lots of issues surrounding KDP on the forum, but some of the posts are quite old I think now, but on the latest Scrivener, it can compile straight out of the box for KDP.
Does this mean, that a Scrivener compiled KDP file is now acceptable to KDP?
It is, if you by that mean Compile to .mobi, but KDP actually prefer/accept that you submit as something else, like .epub or .docx.
I’ve used both mobi and epub output and have had no problems.
I had problems with BOTH (first tried .mobi, then .epub)–not with upload, just with the preview formatting being hosed. I finally just emailed KDP support with a request to fix my preview. No problems since.