Yom Kippur is the most sacred and solemn holy day in Judaism, and is typically observed from sundown to sundown. This year, Yom Kippur begins at sundown on September 27th and ends on the evening of Monday, September 28th.
The first day of classes at Oregon State University (OSU) begins on Monday, September 28th. Classes also begin on Monday, September 28th at Eastern Oregon University, Portland State University, Southern Oregon University, and Western Oregon University.
The only Oregon University System (OUS) institution that is not starting classes on September 28th is the University of Oregon. The first day of classes at the University of Oregon begins on Tuesday, September 29th — after Yom Kippur.
An email from the OSU administration informed the OSU community that faculty, staff and students could be absent for the first day of classes without penalty. I would argue that the penalty is a missed day of learning and/or work, and knowing that at least one OUS institution decided to modify their schedule while yours did not.