Can I use KDP Print to print books that contain Chinese (or other non-Latin) characters?
First, I’ll preface this with the knowledge that I don’t have any experience with alphabets other than the Latin one; in fact, I’ve only worked on a few books that weren’t in English (Spanish translations of English books.)
For uploading to KDP Print, I’d always provide print-ready PDF files; if you can avoid the printer from having to make decisions about how to print your book, you will be better off.
As for using the Chinese or other alphabets and characters, you should be able to embed them into the PDF document. In fact, I just called their customer support line to verify, and as long as you submit a PDF w/all of the relevant fonts embedded in the file then it will print however you set it up in your PDF so that should not be a problem.