I've worn the Pros and the Fit09s, and frankly, didn't see too much of difference of them when they were on. They're both good, protective pads. I think they are pretty low profile and fit more vest-like (if that makes sense) than a lot of other shoulder pads.
As for the protection levels necessary for whatever level you're playing at, I think that's a personal decision. I take worse slashes playing against worse players because they equate defense with slashing the hell out of you and/or your stick. I've taken worse hits from the guys who can't really stop and probably saved myself countless stitches from errant sticks from bad players because I've stuck to wearing a cage. In many cases it isn't me that I'm worried about, its the other guy who thinks there are scouts out there watching him at midnight on a Friday. I'm also not sure how old you are, but as someone who has gotten older, let me tell you, bumps, bruises, pulls and strains don't heal as fast as they used to.