She's a wonderful author and handles the material in a very appropriate way. It's just that Tehanu has intense subject matter that's easily triggering for many people. I think kids probably ought to have an adult read it first and then with them so that it's a proper learning experience.
The deal with the series is that Le Guin did an internalized misogyny in the first one, so the rest is written with more feminist intentionality on top of the cool magic world-building adventure stuff.
If you get editions of her fiction books with any notes in the beginning, I recommend saving them for after you've read the book.