Take the report with a huge pinch of salt. All the Dolphins are Med based. They couldn’t get the sub through the Suez without it being spotted. Something that the Egyptians and the Saudis would take great interest in if they based them at Eilat.
The Dolphins have short range. They would have to be supported by a tender or piggy backed into the area.
The last fantasy story about Israeli subs was when they were meant to have been launching Popeye Turbos in the Bay of Bengal.
My guess is its a false sighting or just a rumor.
The only reason I can think of for an Israeli boat to be there is to launch cruise missiles to take out some stationary radars in Iran just prior to a large air strike.