Danny, the car rental from Ridge Crest is a good suggestion. There is also the Eastern Sierra Transit system that makes runs from Lone Pine to Mojave, where you could rent a car and drive to Visalia (or Fresno), too.
For maybe $150, I think you could even take a taxi from Visalia or Fresno to Crescent Meadow.
Also, Yosemite YARTS service may still be running between Mammoth Lakes, Yosemite and Merced. (But September may only be on weekends.) From Merced, AMTRAK runs to Fresno and Visalia.
Unfortunately some of the public transportation options, where you would transfer from one to the next, would require spending a night in the connecting location. So maybe the car rental and taxi options might take less time.
...Thinking more about this, you could possibly drive your primary rental car to some point on the east side and take public transportation and taxi to Crescent Meadow. For example, leave your car in Mojave, take AMTRAK from there to Visalia or Fresno, then hire a taxi to take you to Crescent Meadow. After your hike, take ESTA from Lone Pine to Mojave. Leaving your car in Mojave would remove the need to stay overnight: Arrive early, take AMTRAK and taxi to Crescent Meadow. After the hike, spend a night in Lone Pine, take the ESTA bus (MWF only) down to Mojave.
