You can dodge Soul Stinger by dashing away from him, then jumping right before his final sting. Jump towards him and, if possible, land on his head to get another jump. You can also circle around him while jumping (Only do this if your ping is low!). You can also jump on him and jump on his final sting (His final sting can kill you if you're on it).

And how you know when soul t will use soul stinger and not soul impact?

Soul Stinger: Points his sword forwards, look for him not bringing it behind him.

Soul Impact: Look for Soul T putting his sword behind him, at an angle.

Soul Breaker: Soul T will put his sword behind him, flat.

Soul Spin: The most obvious, it is instantly apparent he is using this. Although some classes may not be able to react (Baller and Piercer).

So the only way to tell the difference between stinger impact and breaker is where he points his sword?

Yes

Dodge frame perfectly. Seriously