why "eu poderei" is "can" and not "could"??? eu poderei isn't the past ?????

Shouldn't "reunion" work as well as "meeting"?

"I am not able to go to the meeting is unacceptable", while "I am unable to go to the meeting is fine". They're exactly the same.

I will not be able to go to the meeting. = I can't go to the meeting. (Both represent the future tense: poderei)

I keep hearing "ir na reuniao" on both speeds. Grr..

If you wanted to translate "I cant come to the meeting" from English, you would use this phrase, with ir. Yet it is not a correct translation back?