none of the things you listed at all would make you ready, to honestly, even face a mid-level competitive player. lets look at what ya listed....
Beating a Level 9 cpu: cpus, while smarter in brawl then in the other smashes, are still just cpus, they are predictable, lack the ability to take advantage of the oppenents characters faults(I've never seen a falco cpu perform his cg on someone, or camp his *** off like a real falco would) nor do they know how to take advantage of their own characters traits(ever seen a cpu use the cg for the broken eskimos of hell? i haven't.) all cpus really can do is react to your button presses, thats about it., and while they are smarter in brawl then any other smash, they are still cpus, and not real people, the only thing cpus are really good for, is if you have no people to face, and want to practice advanced moves like the cg for the broken eskimos of hell, the DACUS, glide tossing, ect.. on something other then lag-fi
Beating 3 people at one time Unless they were actual real competitive players themsevles, and not your neighbors down the street who just mash buttons like morons hoping it hits, honestly this isn't gonnna help you much, now..against real competitive players, i might be able to see this having some benefit for doubles matches, when your partner dies and your forced to go solo against 2 other people, but other then that, this isn't gonna help you much, again, you need to have faced actual competitive players, not your neighbors down the street who mindlessly mash buttons and play with items on all the time.
Boss battles on intense lol...your kidding right? this would have no benefit whatsoever to your ability to face other people, zero. the only thing you could use this for, would be for the same thing as cpus, to practice "certain" advanced moves, like glide tossing with items, or the DACUS, but honestly, you could just face a cpu or hell go to training mode to do that.
2000 game hours well that just means you are an obsessed smash bros nerd like the rest of us :3 but whether or not its casually or competitively is entirely different.