'Shameless' is a great example of exceptional television that has stayed exceptional for eight seasons. How many shows can you say have done that while keeping things fresh and exciting? It enters it's ninth season this fall, which is a lot of seasons to dig into. If you haven't seen the previous season I'd highly suggest putting your sweatpants on and binge watching it. That might take you quite a while at one hour per episode, but it's well worth it.
It's not that you won't be able to enjoy the show if you start at season 9, but there's so much history to the show at this point that you'd be doing yourself a disservice to just jump right in. This will be Emmy Rossum's last season on the show which might not bode well for the future of the series.