Can you grow avocado trees in zone 9?

Yes, avocado trees can be grown in USDA Hardiness Zone 9. There are several varieties that are recommended for this zone, and the choice of which type to grow will depend on your specific location and microclimate. Some cultivars suitable for Zone 9 include 'AvoHass', 'Brogdon', Fuerte', 'Gwen','Holiday, ', Reed', 'Sharwil, and 'Zutano'.

Remember that zone designations provide temperature-hardiness boundaries based on average cold temperature measurements, but it's still important to consider other localized and microclimate factors for successful gardening, such as frost pockets, soil condition, water availability, wind protection, humidity, heat accumulation during summer, etc.