I just upgraded from version 7 to version 9. In version 7, the indiviual video tracks have a slider where I can adjust the video level on a percentage scale. In version 9, the slider is not present. How do I adjust video levels on tracks in version 9?
There's no slider. However, it's fairly easy to adjust the opacity. Position your mouse pointer on the top of the clip on the particular video track of interest. The pointer will change to a hand with and up/down arrow next to it. Left click and pull down the level and that will adjust the opacity as the slider did in your previous version.
The only ways I know for the Levels slider to disappear is if the track header is too narrow or the track header is too short. Try making it wider and/or taller.