What cause a compressor stall to Vigen?

It seems pretty agile in this video:

To answer your question, it's flying at excessive AoA. You can easily reproduce that in DCS.

But yes, it is pretty agile. Great footage in that video!

The video shows the fighter version of the Viggen (JA-37), which has an upgraded engine (RM8B instead of the RM8A of our AJ-37 attack Viggen). In this upgraded engine they solved the problem of compressor stalls, or at least reduced them a lot. The attack Viggen never recieved the RM8B, as this engine was exclusively used for the fighter Viggen as it needed it for air combat.

They also never pull much alpha in the video

The video shows the fighter version of the Viggen (JA-37), which has an upgraded engine (RM8B instead of the RM8A of our AJ-37 attack Viggen). In this upgraded engine they solved the problem of compressor stalls, or at least reduced them a lot. The attack Viggen never recieved the RM8B, as this engine was exclusively used for the fighter Viggen as it needed it for air combat.

This version should apear in DCS then!

They also never pull much alpha in the video

Hmm, difficult to say. 3:08 looks like quite a bit of alpha.