Thinking back to when I was 9 in the early 90s, the RPGs I played at the time weren't nearly as text-heavy as an MMO. There were occasionally words I didn't understand, let alone how to say them because voice acting wasn't a thing, but roughly had to derive context in those instances. And while I enjoyed myself, I wouldn't expect kids today to be in a better position even if gaming is arguably more accepted today. With how releases were done at the time, a lot were probably a year or two old in Japan by the time they hit the US or entered my sphere of awareness, too.

Mechanically, most were turn-based, so this obviously took some of the stress out of acting in the moment. AI party members you couldn't control were occasionally a thing, but most certainly not to the extent of Trusts. Ironically, I'd argue the slower pace and menu system yielded more tactical combat than XIV provides outside of "do the dance" ad nauseum, but that's basically shifting one difficulty for another. Do I think 9 year old me could play XIV well? Eh, probably, but not without some trial and error on harder encounters. I think it's somewhat undersold that Trusts can help players learn mechanics, too.

As others have said, though, definitely not the target audience. Nor should it be assumed pictures would convey more than text when it comes to UI gripes.