Tom______to have delivered the speech in their theatre room.

“be said+不定式”是英语中一个很有用的结构，表示据说的意思时，be要用一般现在时

“be said+不定式完成式”

该搭配表示不定式所表示的动作已经完成。如：

They are said to have teft London. 据说他们已经离开伦敦。

He is said to have written another TV play. 据说他又写了一部电视剧。

Mr. Brown is said to have died of liver cancer. 据说布朗先生死于肝癌。

楼下的叙述很清楚，记住be said to\be said that 是固定的用法搭配，表示据说，听说。一定要用现在时态的be，不能用过去时态的be