I will try an make this simple.
No, you can not remove scratches from the vinyl. The best think you can do it use a filler glaze like CG BLACKLIGHT to hide the scratches and improve gloss.
The sun will fade the vinyl very quickly. I recommend to apply a paint sealant like CG JetSeal to minimum and help prevent fading.
From my experience, vinyl wrap only last about 2 years or 3 years MAX before the sun starts eating it away where I live in Southern California. If you wanna keep you vinyl looking good, either park in the shade or use a car cover when park for long period. UV rays are the vinyl's worst enemy.
Hope that helped!!!