This is an allegro, so it is rapid, and I assume the games were not recorded (etc) so the following applies concerning claiming a win on time:
A.4.3
To claim a win on time, the claimant may stop the chessclock and notify the arbiter. However, the game is drawn if the position is such that the claimant cannot checkmate the player’s king by any possible series of legal moves.
(my emphasis)
6.8 does not apply because it is in the Competition Rules which are overridden for rapid.
The claimant doesn't have to stop the clock or notify the arbiter - it says "may". If the arbiter is satisfied that a claim was made (such as by saying "Time!" or "Flag!") then that's enough basis to record it as a win.
FIDE could have worded this "may" as a "must". However they didn't. I think the reason they didn't is that they didn't want a claim to be invalidated if the player made the claim without stopping the clock.