OG you are better off shopping for 10R22.5s. The 9Rs are a weirdo size now and (as it has been mentioned before) will probably cost you more. 10R is a common size in modern medium duty trucks and you'll pick up some diameter (top end speed). 10Rs will also dually up fine if you are worried about that. I made the switch on my '66 C50 and the dually setup has plenty of clearance from tire to tire.

Brian