CHICAGO — After a nine-hour bargaining session Sunday — and months of negotiations — the University of Illinois at Chicago administration reached a tentative agreement with faculty and staff who had been on strike since last Tuesday. UIC United Faculty, the union representing 1,500 tenure and nontenure faculty at UIC, has been bargaining since April for a new contract that ensures increased pay, more funding for student services and job security, and had worked without a contract since Aug. 16. After the union failed to reach an agreement during a marathon bargaining session Jan. 16, union mem…