Lösung gefunden. Bei den Scripten aus der Library das universal-blu-to-mqtt.js ausgewählt. Anschließend bearbeitet und den entsprechenden Bereich mit den Werten für den WS90 ergänzt.
// The BTH object defines the structure of the BTHome data
const BTH = {
0x00: { n: "pid", t: uint8 },
0x01: { n: "battery", t: uint8, u: "%" },
0x02: { n: "temperature", t: int16, f: 0.01, u: "tC" },
0x03: { n: "humidity", t: uint16, f: 0.01, u: "%" },
0x04: { n: "atm_presure", t: uint24, f: 0.01, u: "hPa" },
0x05: { n: "illuminance", t: uint24, f: 0.01, u:"lux" },
0x08: { n: "dew_point", t: int16, f: 0.01, u: "tC" },
0x0c: { n: "capacitor_voltage", t: int16, f: 0.001, u: "V"},
0x20: { n: "rain", t: uint8 },
0x21: { n: "motion", t: uint8 },
0x2c: { n: "vibration", t: uint8 },
0x2d: { n: "window", t: uint8 },
0x2e: { n: "humidity", t: uint8, u: "%" },
0x3a: { n: "button", t: uint16 },
0x3f: { n: "rotation", t: int16, f: 0.1 },
0x40: { n: "distance_mm", t: uint16 },
0x44: { n: "wind_speed", t: int16, f: 0.01, u: "m/s" },
0x45: { n: "temperature", t: int16, f: 0.1, u: "tC" },
0x46: { n: "uv_index", t: uint8, f: 0.1 },
0x5e: { n: "wind_direction", t: int16, f: 0.01, u: "Grad" },
0x5f: { n: "precipitation", t: int16, f: 0.1, u: "mm"},
};