Can older seasons be played on this game. If so how do I go about it

Yes, the historical rosters are built into the game.

When you are creating a new game via sandbox or challenge or whatever there is an option shown along with the normal start dates that says 'Historical Replay' select that option and below you will see that there is a drop down box asking you which season you would like to start from beginning in 1976/77.

Here's a screenshot of the menu.

https://imgur.com/a/zPM6SIK

Oh sweet thats funny cuz 76-77 was the first season i really followed... possibly 75-76 but oh well was a super sonics fan in 76-78

Also is there graphics such as older courts for the older seasons.. i know ill have to probabyl import my own player faces but what about older courts?

As far as I'm aware the only graphics mods available currently for both player faces and courts are more modern ones.