Or HaChaim on Genesis 41:9/אור החיים על בראשית מ״א:ט׳

1 וידבר שר המשקים את פרעה, The chief butler said to Pharaoh saying, etc. The reason the Torah had to add the word לאמור as well as the word את פרעה instead of אל פרעה, maybe that the chief butler did not address the King personally but his advisers. He asked the king's advisers to relay his words to the king. This is the reason that his entire speech is in the third person.

2Another reason he said לאמור את חטאי "to relate my sins," maybe the following. He wanted Pharaoh to be sure not to understand his words as a complaint for having been wrongfully incarcerated, but rather stressed his own insignificance. This is why he emphasised that he had indeed committed a sin. The chief butler added the word היום, "today," to explain that the reason he had come forward now was that there was an overriding need for the information he had to impart. Had this not been the case he certainly would not have brought up his own incongruous past. The reason the chief butler spoke about his sins in the plural, i.e. את חטאי, was that he wanted to convey the impression that although he had committed only one sin, this fact weighed as heavily on him as if he had committed several sins. Perhaps he simply considered that his tardiness in coming forward was an additional sin.