This is more so the boat I'm in on this. I think we had spurts of LeBron making a case for himself as early as his 3rd year in the league. At 21 years old. Comes into his first playoff game ever plays the full 48 minutes and finishes with 32/11/11.. wins the series on 36/8/6 50+%, his first series ever.. He wasn't the best player in the league at that point, but he was the only player capable of that type of performance even then.
Next year he's in the finals, at 22 years old with no "sidekick" anywhere even remotely close to the level of player he was, which was probably the first time the league had something like that since Larry Bird, or Hakeem. Albeit the teams he knocked off weren't totally outstanding.
Those two seasons back-to-back I think are when he started to have an argument. But like you said, the 2008-2009 season, that's the year to me that he basically took the leap. They ran into an Orlando team that they just couldn't match-up with, would have been really fun to get the Kobe-LeBron showdown.
In a way yes, in a way no. He wasn't a great shooter, but he couldn't be stopped from getting to the rim and scoring efficiently either. That's kinda like saying Jason Kidd didn't have a good jumper, or a good post player didn't have a good jumper.. They didn't have to rely on that to be the players they were. His FG% from his 2nd year through his last year with the Cavs were all good enough to be Kobe's best year ever.
Piggy backing off of that, nearly half his shots from 10 feet and out were behind the 3 point line. Where as we know 33% from 3 yields the same output as 50% from 2. Meaning that his eFG% and TS% numbers were better as well.
Defensively, I think 2009 is actually right around the time his defense really started to look like an All-NBA level defense.. Prior to that he was making strides, but that to me is when he took the jump. Part of that was adding a couple of plus level defenders around him, and the fact that in 2008 they had so many injuries that there was never any sort of consistency on either end. (21 different starting line-ups).. He's always been a top tier defensive rebounder, and in the passing lanes, but that is the year his focus on being great at both ends really shifted.
I'm also not sure on the shaky in the clutch either. He had plenty of big time clutch moments before that season. Making timely winning plays wasn't an issue as he had been closing out playoff games with regularity up until this point. Regardless in the grand scheme of things, a point scored in the first minute of a game is the same as a point scored in the last minute.. Sure there is something to be said about not ****ting the bed in big moments, but otherwise "clutch" is more just something for us to argue and measure more than it is a claim to being good/bad at basketball.