I apologize if this has been asked before.

Here's the scenario. My Ywing (pilot skill 8) shoots my opponents Tie advanced (pilot skill 7) tailing my xwing (pilot skill 6). Essentially interupting him from shooting down my xwing before it could do it's attack on a wounded Tie. Now this was the first time I used ywings my thoughts were oh Ion cannon like with Hoth when they used the big Ion cannon to distrupt the star destroyers from shooting the transports! I'd shoot his Tie and it can't do anything now until next turn it can only move 1 forward but can then continue doing actions and such. I figured perfect a great way to save my xwing. But he understood the card as it can do its normal combat and such just at the begining of his next turn he can't control his movement basicly

We discussed it but in the end concluded that the card didn't say it stopped attacks so technically I'm wrong on that part. But we also agreed that in the spirit of star wars it should and was played out that it interrupts him from doing a combat phase. We didn't see any issues playing it that way it saved my but in a pinch here and there but over all I had better luck shooting my primary weapons on the y wing than the ion cannon.

But my questions is if I was to say go to a tourny what should I expect? Does my ywing actually interrupt his Tie's attack?

No. As you said, it doesn't say anything like that on the card. At a tournament, rules-based arguments will prevail over theme-based ones every time.

The Ion Cannonis very strong stand alone. The ability to effect your oppenents movement can be big. For example, I locked down two of my oppenents ships because the collide faceing each other at a slight angle. Unable to move past each other one of the ships continued to collide with an astoriod while both had nothing in their fire arc. This is a best case scenerio. I think if the Ion Cannon was any stronger it will cost to many points or be over powered. That said, the rules card for the Ion token is very specific in application. Don't fill in the blanks, just follow the text word for word.