Depending on the size of the tank a sand sifting goby or the like will clean the top of the sand. The front glass is tricky as its an area of low/no flow and is getting light bleedoff from the tank. Perfect conditions for cayno. There is also plenty in the sand to fuel the cayno to. A sand sifter might help with that but I doubt it will fully get rid of it. I would get a sand sifter and clean the glass down there manually and it should eventually go away
That looks about right for 9 months.
You can vacuum it but I don't know if you are using the sand as a biological filter.
You don't want to disturb a lot of it