To echo what others have said, unless you did the adventures of Cyclops in the orphanage with Mr Sinister, there's not much source material to draw from. With regards to origins, I enjoyed the conceit the X-films have had so far opening with parts of different characters origins. 1st movie had Magneto and Rogue, 3rd movie had Jean - although I wish they had done the bit where her friend is hit by the car and Jean finds herself in her friend's mind as she dies. To a lesser extent in X2 where they intro Nightcrawler and show Wolverine investigating Alkali lake.
If the series had continued, as I believe it should, an opening sequence with Scott being thrown out of his parent descending plane with one parachute to share with his younger brother and the injury that resulted in his optic blast being uncontrollable would have followed. Include the bit from some depictions that show that it was his manifesting optic blast that damaged the chute for extra pathos. Leave the reason for the plane crash vague so you have the option of bringing in aliens later when the series needs to take a turn to the space operatic.