This is what we recommend based on your details:

Ceiling Height.png

2.4 - 2.6 m

Room:AreaSize.png

3x3

Based on a ceiling height between 2.4 - 2.5 m, and an area size of 3 x 3, we recommend a 9,000BTU unit. 

Some options:

Available in 9,000 & 10,000 BTU

Carrier XPower Gold

McQuay MEIS Mini Split