A Boy Scout is not merely someone who follows the rules, but one who respects authority. Scouting is a graduated, if not hierarchical, system with clear delineations between leaders and followers (at least, that's what I remember of it). It's got an internal language rich in symbolism. Superman is the Big Blue Boy Scout because he subordinates himself to authority even though he is more powerful than that authority. He adopts the ideals and language (truth, justice, and the American Way) of that authority. He is frequently seen with the symbols of that authority, even being buried under a statue of himself and a bald eagle. And he doesn't question the appropriateness of any of this. The ultimate expression of the Boy Scuot is in The Dark Knight Returns, in which he will do anything "anybody with a flag" tells him to do. It's not about following the rules or even calling his mother, it's about falling into line and doing what one is told, happily.
Kirk was not the type to be impressed by someone with a flag, and at times put his values--which were probably in line with Starfleet values--ahead of a strict interpretation of orders. The fact that he advanced through the ranks as quickly as he did--and even survived a guilty verdict in a court martial--indicates that his values and decisions were broadly in line with the precepts of Starfleet and the Federation. If he had been a rebel, Starfleet would never have made him a flag officer, they would have ended his rebellion early on or let him stew in a Lt.'s shore billet.
So, not a boy scout, but not a rebel either. (Of course, we never really defined "bad boy" so we might be talking past each other.) Just a competent, get-the-job-done officer who thought highly of himself.
Perhaps, but it is presented with a somewhat gleeful glint in Kirks eye and followed up by the phrase "I don't like to lose."
Self-awareness, or awareness of how he is perceived? Regardless, motivations can be complex, and the older Kirk's analysis of how he made his decision may be flawed by the passage of time or his perspective as an Academy officer vs. student. Or he might just have been encouraging his companions with a bit of bravado. I think my interpretation is consistent with what's onscreen and not unreasonable. And so is the other one.
Not sure how that ties into Kirk being a "bad boy"
It just goes to show that pride in his mind was a core characteristic of Kirk and explains his failings better than archetypal labels like bad boy, rebel, maverick, etc. He wasn't lazy when approaching Reliant because he had disdain for the rules, but because he had evaluated them over the course of his career and considered his own judgment to be better. This is what you get when the walking stack of books grows up, he thinks he is "smarter than the checklist" and free to ignore it in favor of his own judgment. Just like young Kirk thought he was smarter than the Academy's curriculum designers. He's not rebelling against the established systems, he's seeking to work within them and improve them with his superior judgment (and failing).
The way I look at it, the stack of books in the Academy, the burdened commander of TOS, and the smarter-than-the-checklist Kirk of TWOK-TUC are all points on the same long-term character arc, and the younger versions can safely be described as not-Boy Scouts. I guess Trek '09 short circuited the arc by placing the dangerously self-assured Kirk at the beginning without the benefit of experience that made the original Kirk into that character. Not what I would've done, but I guess it worked for enough people.