Yes he does state that the MM overrates heroes in it's current state, and I'm not disputing that. He has also said numerous times how heroes are overrated by the forumers and high level heroes are not needed to win wars, but this statement is very war dependent. He has said if you are attacking your same th level in war that you have basically already lost the war. The way he plays the game with his rushing strategy and engineered clan makes it so that heroes are not needed to be high level, but that is just not the case for most players. Most players are not in an engineered clan pulling lesser opponents, they aren't doing dips for every attack in war, they must attack someone of the same th level as them.
I would argue that your th9.5 scenario is vague and circumstantial. Is that 9.5 attacking a 9 or a 10 because it probably should be matched up with a th10 since it is also a th10? Will every base have air d on the edge? Is the CC lureable? If AQ is in the core, and AD are not on the edge, and CC is unlureable then I am not so sure that a th9.5 is 3 starring a maxish th10 with 10/10 heroes with laloon without a major kill squad component to push into the base to get those objectives which may leave you too light on your laloon portion and fail to get the 3*. However a th9.5 with those heroes but upgrade other offense probably is still matching with a th9. The question becomes is a th9.5 with those weak heroes but increased camp and spell space and upgraded troops an even match with a th9 with high level heroes or should it be matched with a lower to mid th10? Sin basically implies it all the time on here (wouldn't be surprised if it has been stated outright as well) that 10 times out of 10 you want to be the person with more troop space, spell space, and max troops attacking a th below you rather then be the totally maxed out th9 attacking at your same level. I would agree with this completely. I for sure want to be the guy with more of everything attacking less, I think that's pretty obvious.
Two scenarios:
Take Sin's lineup posted earlier in this thread, I think based on the lineups he gets that he is correct and that his heroes don't make that much of a difference because of his ability to understand the MM and tweak his bases accordingly to pull a th level below them on a fairly regular basis. Those extra hero levels don't help you 3* bases below you as much as extra troops, spells, and higher level troops.
Now take a maxer clan facing a maxer clan and one team has max defenses with high level heroes and the other has baby level heroes. Do heroes matter then? This has been my point this whole time is that whether or not heroes are going to make the difference in the war is different in every single war. If your clan is engineered and you typically face lesser opponents then heroes matter less, if your clan utilizes some engineering it could swing either way if heroes matter or not depending on opponent, if your in a maxer clan facing maxer clans then heroes will matter significantly.

