There were supposed
to be whales in the 24th century? I don't see it; it's convenient for humans if there are, but nobody mucked with the timeline to stop them from being there.
Doesn't change the main point, though. Kirk is trying to change his present in TVH, not his past.
As for cheating, I read Spock Prime as not talking about timelines per se. What he learned from Kirk Prime is that when the rules are against you, cheating is the logical response.