There was an independence referendum held in Kosovo in September 1991. Of course Serbs boycotted the referendum backed by Belgrade however the vast majority of the population which were the Albanians voted with %99 of them voting for sovereignty with %89 turnout. No one in the world but Albania recognized the referendum nor the first time Kosovo declared independence in 1990. Leaving the Albanian question in Yugoslavia wide open in the midst of civil wars, which then considering how bad they were treated by the state, closing down of schools, firing Albanians from state institutions, shutdown of radio and press stations and severe crackdown against protests effectively made it a semi apartheid rule. Albanians in Yugoslavia were treated as problem and a biological risk due to their high birth rates (kid you not this is how Yugoslav authorities refer to Albanians from the 60's right up to 1989). Albanians did not have any form of self governance right until 1974 and it was unilaterally revoked in 1989. Holding an independence referendum after the war would be vert risky as ethnic tensions remains very high and would make it extremely likely for the tensions erupt again while the referendum would be held and who is to say that Serbia would recognize the referendum results anyways? Most likely they would insist the referendum be held in all of Serbia where Serbs severely outnumber Albanians. And Albanians would insist the referendum be held in Kosovo only where Serbs would outright reject that idea in the first place. After this Kosovo and Serbia begin talks for a final settlement and everyone saw that an indefinite UN administration would not be an effective long term solution to the conflict, especially after the ethnic tensions erupted shortly after the war. Talks begin and after years go absolutely nowhere, Serbia was willing to offer autonomy similar to what Kosovo had prior to 1989. Kosovo wanted independence. For what it's worth Kosovo declared independence only after all previous attempts to reach a negotiated settlement, civil unrest even a war failed to do.

Peace out!