According to the Pentagon, two SU-25 jets intercepted the Predator drone and fired "multiple rounds".That sounds like a cannon engagement. Predator cruises around 90mph. Frogfoot is a slow-flying (600mph maxium) high aspect ratio plane that can probably manage a low speed around 180mph (given that the A-10 has a stall speed of 140mph). So with a 90mph closing speed, a target that cannot practically evade due to the lag in command times, and a cannon firing 50 rounds/second, neither of the Su-25 pilots could so much as register a hit.
They missed their target, and the drone was guided back to base.
I bet the Israeli defence ministry is hoping that the Iranian SAM commanders are equally competent.