I heard to caych Latios you need a wobbafett. If this is true does wobbafett..

It doesn't have to be, it just helps. Because Wobfuffet has a power called Shadow tag, which stops the Pokemon from getting away, making it easier to catch!
So you don't need it, but it is advised.

You don't need a Wobbuffet, but you'll either have to have it first in your party or immediately switch to it in order for Shadow Tag to take effect. Personally, I'd suggest a Sableye with Mean Look.

Well it's not the only way to catch Latio's because you can just throw the masterball at him straight away but if you've already used it then yes battle him with Wobbufett 1st in your party.

Yes, Wobbuffet has to be first in your party because of their Shadow Tag ability which prevents switching or escaping. I tried switching my first Pokemon to Wobbuffet and Latios ran after the switch so he does have to be first in your party.

Who told you that you don't need a wobbafett to catch Latios all you need to do is beat the Elite Four then you'll be in your room press watch the T.V. It will say something about they have seen a mysterious flying blue Pokemon.Then look around in the grass,sea etc. Eventually you will find it

P.S you have to be patient because it tends to move around a lot

You do need wobbafett because he has the ability to prevent Pokemon from escaping when you encounter it if you don't have wobbafett it will escape in one turn and put him first in your party.