It's not Io with an alef, it's with a vav... That's to him. It's like their vs there. They sound the same but written they mean different things.
I agree, especially since an earlier phrase -- האישה אומרת כן -- was translated as "The woman says 'yes.'"
would אני אומר אותו be fine. If yes, whats the difference and if no, why not
No. לו is like "to him" and אותו is like "him." If you think of the verb here as "say," then it will follow the same format as English. "I say to him"
oh so is it something like לו is an indirect object and אותו is only for direct objects?
Yes, אותו is derived from את which is the word that marks a definite direct object. The verb אמר takes a direct object which is the thing being said, and an optional indirect object with ל which is the person being told. The direct object can be omitted if it is clear from the context, which is what happens here.
Certain verbs simply require certain prepositions The word לו is a combination of the preposition ל and the pronoun הוא The word אותו is a combination of the preposition את and the pronoun הוא