Henry IX of Lubin (Polish: Henryk IX lubiński ; 1369 – between 9 January 1419 and 10 July 1420), was a Duke of Brzeg (Brieg) during 1399–1400 with his brother and since 1400, Duke of Lubin (Lüben), Chojnów (Haynau) and Oława (Ohlau).
He was the eldest son of Henry VIII with a Scar, Duke of Brzeg, by his first wife Helena, the daughter of Otto V, Count of Orlamünde.
Henry IX was his parents' only child. His mother died prematurely in 1369, shortly after his birth, perhaps even during the childbirth. The prince grew in the intellectual and artistic court of his grandfather, Louis I the Fair. He took part in the many scientific disputes, sumptuous feasts and balls, theatrical presentations and also knight tournaments. Louis I's library was one of the most extendsive in Europe. The Duke, who was a renowned patron of the arts and culture, cared intensely about the education of his heirs.
In 1379, Henry IX's father remarried. His new wife was Margareta of Masovia, daughter of Duke Siemowit III and widow of Casimir IV of Pomerania. From this union, Henry IX gained two half-siblings: Louis II and Margareta. Despite the considerable age difference between them, the brothers had a warm and close relationship for many years until the succession war at the beginning of the 15th century.
On 5 July 1396 Louis I the Fair give Henry IX the towns of Kluczbork, Byczyna and Wołczyn, on occasion of his betrothal with Anna of Cieszyn, daughter of Duke Przemyslaus I Noszak; but was only on 29 September (nine days after the marriage ceremony) when he was confirmed with the formal possession of their domains, who produced a rent of 2,000 fines. In the marriage contract, was also stipulated that lands became in the widow's lands (Oprawa wdowia) of the bride. A few months later, Duke Louis I give his grandson the half of the rents of the towns of Brzeg, Wierzbno and Oława.