JSFiddle - React, Tailwind, and code Playground

JavaScript

var randomize = function (str) {
    if (str.length == 9) return str;
    var newDigit = Math.floor(Math.random()*9 + 1);
    if (str.indexOf(newDigit) == -1) {
        return randomize(str + newDigit);
    } else {
        return randomize(str);
    }
}

console.log(randomize(''));