AL78, on 2021-April-09, 17:04, said:
Would you be happy being in a slam at imps which depends on playing a nine card fit for no losers missing the queen?
Yes, but I wouldn't be too upset about missing it either. The odds are about 53% in favour of finding the queen, so bidding it does win in the long run.
As for bidding the slam, you may be hampered by your system but South underbid their hand significantly. Even if you're not playing 2/1 game-forcing, you need a way to show a good hand with heart support in this auction - IMO 3H is better played as forcing than invitational. South might also have splintered over 2H or even simply asked for key cards.
General wisdom is that it is rarely right to hide four-card support for opener's major, so most people would raise immediately. The hand is too good for an immediate splinter, so bidding Jacoby 2NT looks right. Over that, your instinct about not showing the singleton club is a good one. Once you show extras, South certainly should be looking for slam.
One other thing about the slam auctions. Standard advice is to stay out of a slam missing one ace and the trump queen, but that's not best particularly with a 9-card fit. There are two possibilities - you're missing an ace and the slam is 53%, or you're missing the KQ of trumps and the slam is 76% (only losing when they're both offside). This is less true in an 8-card fit both because you have less chance of finding the queen and because a bad break is more likely to cause problem. But here the slam should be bid after a keycard enquiry.