I recently got a rocket mozzafiato (vibe not rotary) and notice that lately when pulling shots the pressure never really gets about 6 or 7 bar, and shots seem to be running a little fast. When I backflush using blind basket, it gets up to 9 bar. Haven't made any major changes in grind settings either. Not sure what's going on - has anyone encountered this before?

Thanks.

If the brew pressure rises to 9 bar against a blind basket and not against the coffee puck, the latter isn't offering enough resistance. This is due to the grind being too coarse or the coffee being stale.

Does that mean the pressure used to be higher on the Mozzafiato and it's now only around 6-7 bars without having made any major changes?
If so, it's most likely the latter of what Dan wrote.
Some parameters can change over time (i.e. humidity) and some will definitely change over time. Like roasted coffee beans are releasing CO2 after the roasting process and that again will change other factors like acidity. If the coffee beans become "older" or other parameters change, you might have to readjust your grinder...