Removing scratches from glass is a lot of work and messy. CarPro offers ceriglass and to achieve the best results a rotary with the glass polishing pads. A dual action polisher can work. Mike Phillips has some good write ups on glass polishing that you may want to google.
You have a couple options. A glass sealant like CarPro FlyBy 30 or a more durable glass coating FlyByForte. Be sure to prep wipe the surface after polishing with Eraser.