Auron and Mika thought not, but I wonder. At least the idea of using machina to destroy Sin had something going for it. (MAJOR SPOILER coming)
(SPOILER)Remember that what usually happened over and over was this: a summoner used one of their guardians as the fayth of the Final Aeon, and tried to defeat Sin with it. But if they succeeded, Yu Yevon would possess the Final Aeon, kill the summoner and use it to form a new Sin.
So if Sin could somehow be destroyed by machina, there would be no Final Aeon for YY to take over, and he would apparently be up the proverbial creek. Also considering he is not exactly the ultimate boss when left on his own
Obviously the problem is getting a machina (or two) powerful enough to defeat Sin, but the one the Al Bhed used looked to me like it was getting close. Maybe if the Al Bhed had teamed up with the Yevon priesthood intead ... (SPOILER)they had some pretty good machina hidden away. It could have worked, no?