The 24-year-old Dutchman joined Wolves from Liverpool in September 2020 and made 33 appearances during his six years at Molineux.
Hoever had spells with PSV Eindhoven, Stoke City, Auxerre and Sheffield United, including two separate stints with Stoke.
He returned to Wolves last season and made eight appearances before joining Sheffield United for the second half of the campaign.
“When a player has a year left on his contract, you have to try and find a solution which works for all parties, and this does. Ki’s always been a great professional, so we’re delighted for him and he leaves with our best wishes,” technical director Matt Jackson said.
“He’s had plenty of opportunities here but has never been able to convince any manager.
“We’ve managed his loans well, with good exposure, and his communication and application have been excellent, but sometimes players need to know they’re somewhere permanently.”