A release gets the player out of his scholarship at the original school. Doesn't absolve the player of sitting out a year. The common practice is for players to be granted the release from their scholarship, maybe with a 2 year sitting out period if the transfer occurs within the conference. Some schools will restrict some other schools as well.
I don't know what happens if a school refuses to grant the release, but it's very rare.
He stays or goes to a junior college or a non D1 school
So Sodie had a 9 win season and two years later had a 20 win season... hmm.... So after the 9 win debacle season, he goes 16-13 in TL and KL's freshman season. They actually were a very respectable 10-6 in the A-10, so there was a lot of optimism heading into the next season that they could contend for the conference title. Instead, for Ian's senior season, they were a very disappointing 8-8 in the A-10. With Ian graduating and the recruiting pipeline running dry, the program was clearly heading in the wrong direction when Sodie was fired after the "20 win season."
I said I give him credit for the 20 win season so I am not sure what your point is. The problem the program had under BS at that point was that attendance was not growing and in fact had taken a dip the previous years and he had not been recruiting well - he was leaving schollies unfilled and not even filling them the next year. He had one kid ready to sign and that was it. To say that BS had a team ready to contend for an A10 title is a bit of an overstatement. We had no idea what to expect the next year given that the roster was getting thin. My only problem with letting him go was the timing but as it turned out it was the right thing to do. BS was never going to be the answer.