After Beathing Labryrinth, a question please.

As Scion, after beating Labyrinth, do I have to refund skill points in "passive skill tree" to allocate for use on new paths after opening Ascendant? Thank you.

no

Your question isn't very clear. You want to refund skill points if you opt to start from another classes starting location yes. Do you "have to"? no.

Go look up build or look at Scions on PoE Ninja to better understand when and why you do this.