The wall needs to be a straight line.
Another SoP talent, Wall of Darkness, specifies that it may be “..up to [3 plus CL] 10-ft cubes… arranged contiguously, but otherwise may assume any shape.” Energy Wall has no such language, so one would think it is a more traditional wall.
You most likely deal your damage only once.
Once again, I’m forced to point to a lack of rules. Energy Wall has a specific association with Air Blast “If using Energy Wall, each square of wall is considered the center of effect for those who enter that section.”
Because other effects have no such language, it would seem that’s an exception and not the norm. Additionally,
Creatures passing through your wall…
seems like it would only happens once per movement. This is supported by a balance concern of dealing full spell damage multiple times in a reactive stance. If the damage was reduced by turning it into a wall, that would be different.