Yes, it's one thing to try and trick the other team, and there are upsides and downsides to this play, but don't every try to trick your own partner! The only exception would be if you're playing with a weaker player, and need them to trump your lead with the highest card they have, a good player knows to trump the ace, but a weaker player may not understand that concept.
Although this statement is true here, ..." but don't [ ever ] try to trick your own partner! The only exception would be if you're playing with a weaker player"... I know of several situation on defense that it is not true. Suppose the dealer has the Jack up (JH with 9H, AS dblt XX) and S1 has JD QH AC KC 9C and his S3 partner has a void in clubs with AH. If S1 leads AC, generally S3 is not going to trump his AC. I want my partner to trump my club lead. It might force the Dealer to over trump with the JH. And certainly I don't want the dealer to use a low trump when he holds the JH.
So I disagree that there are exceptions but CERTAINLY NOT in this Hand.
Irish, I suppose that could potentially be another one, but a good player also knows when it's correct to trump his partner's ace lead. I wouldn't need to be fooled into trumping that KC if my hand required it, and if my hand does not require it, then it would have been a mistake to get me to trump your own ace. I feel like this is one of those situations where an expert player just has to know when to trump high on an ace, rather than their partner trying to trick them into it.
I'd like to add another nontrump set that is misplayed. King-Queen. Like the Ace-king set, they are seen differently by your partner. Assume you hold ace-nine in say clubs. Your partner leads his queen of clubs and holds back the king. Your best play is to use the ace. Now say he leads the king, you are able to decide based on the cards in your hand the best play.