I like largest screen possible. I have 9 Pro XL with
"Poetic Guardian Mag Pro" case on it. Case is on beefy side. And also use a "Mag Safe Pop Socket" with a strong Magnet attached on end of Pop Socket so I can stick the phone to any steel surface. So it really is quite thick.
If there was a 9 Pro XXL I would have gotten that.
No issue fitting in my pocket or one hand use.