South’s one-no-trump overcall may be the least of evils here. Passing with 17 points is too dangerous, and the less said about a takeout double, the better. When North uses a Texas transfer to hearts, at least South has top tricks rather than potentially less useful secondary values.
The spade eight lead is covered all around, and declarer turns his mind to the trump suit. The heart ace is probably offside, with the opening bidder, but even without this inference, the best play would be to finesse the heart 10, hoping for the jack to be onside. The heart 10 forces the ace, and back comes the club jack. Declarer wins and discards a diamond on the spade king. He then ruffs a spade to dummy to cash the heart king and queen, seeing East discard on the third round of trumps. What now?
With careful play, declarer does not need to rely on scoring more than one diamond trick as long as he can score all of dummy’s low trumps via black-suit ruffs. After East’s opening bid and club jack shift, the diamond ace is likely to be onside. Also, finessing the diamond 10 might not be enough even if it forces the ace, with West able to cash the heart jack.
A diamond to the king allows declarer to ruff another spade, cross to the club king and lead a club. It would not help West to ruff in at any point; dummy would just discard a diamond loser. When West discards a plain card instead, declarer scores the heart six en passant for his 10th trick.