Using rangefinder camreas such as the M9 are quite different from an SLR.
So is using medium format camera, such as the S2... though it's more closely modeled upon an SLR format than most. My biggest concern, besides price, is that this fairly new system isn't very extensive as yet.
You'd better be certain what you are getting into... If you've never shot either of these types of cameras, you should try before you buy. Considering what you thinking about doing, I would be surprised if a dealer wouldn't give you a loaner to test drive, if they thought they might be making a sale.
I really like rangefinder cameras for street shooting, photojournalistic type shots. It's hard to beat them for that sort of thing... but they aren't particularly useful with longer lenses and I use a lot of those, so I'll stick with an SLR.
I also like medium format (though I haven't used any of the digital models... just film in the good/bad old days)... great for portraiture, weddings, even some landscapes when I don't particularly feel like lugging around a 4x5 view camera and a bunch of film holders.
There have been a few wildlife photographers who usd medium format, but long lenses are again somewhat limited. Shooting speed is relatively slow, too. Not as slow as large format, of course. But not really what I'd call "sports oriented" either.
Looks like OP isn't all that interested in anything less than an OEM lens (and then mostly L-series). But be aware too that there are limited third party offerings for rangefinder cameras, and even less for medium format... particularly the relatively new S2 system. You'd find considerably more system choices with Leaf/Mamiya and Hasselblad... at least for the foreseeable future.
Really would need to know more about what the OP wants to do, what they like to shoot, to say whether the switch to one of these other systems would be wise or not.