A Squeeze-Trim-Endplay (Advanced)

This squeeze-trim-endplay is from Adventures in Card Play, by Ottlik and Kelsey. They describe the squeeze and trim as "hammering" the defender's hand into shape. Because it is Ottlik, it is a very complex hand.
KQ6
A104
A764
Q53

A98432
732
J
K76
Righty opened a weak no trump (13-15 HCP) and Lefty bid an old-fashioned 2 Diamonds, showing a weak hand with diamond suit. Your partner balances in with a double and you make it to 4 spades. The opening lead is the 9 of hearts, apparently a modern top of nothing. In any case, Righty is likely to have the KQJ of hearts. If diamond honors are split, most or all of the remaining HCP belong to Righty.

Discussion/Answer