I'd argue that we have every reason to think Kirk didn't do Drusilla. After all, that's what his enemies expected of him. Also, his enemies expected this to be Kirk's last night alive, while Kirk would have believed otherwise, and would have wanted to show he believed otherwise. Also, Kirk would have had an issue or two against slavery as a matter of principle, and would probably have been discussing politics rather than getting physical.
Finally, Kirk would have had every reason to think that Drusilla was an agent of destruction, either willingly, or then simply because pseudo-20th-century medicine wouldn't have defeated veneric diseases yet.
Timo Saloniemi