Well, they all think the M9 is 50 years old anyway, and it shoots my classic glass just great.
My oldest are from 1937 and I have quite a few lenses from the 50s and early 60s, mostly Zeiss, Canon and Nikon, except I do have a red scale elmar.
My Ms start with late Mandler works: 28 elmarit v3, 50 cron, 135/2.8 and the 75 Lux.
I have a weakness for 50 Sonnars, from CZJ to Sonnetar.
The M9 loves every one, except the 28 Elmarit which is quite weak on the edges. Taking that to heart my wider stuff is all modern, ZM 18, SEM 21 and 28 Cron. All of which can take your breath away on the ol M9 😉