Is a 22 inch road bike appropriate for a 5'9" person?
Unfortunately it is not possible to give you a definite answer.

A typical road frame of that size (56 cm) is usually too large for someone of your size (175 cm).

However, the bike may not be typical. Neither is there a typical rider. A bike that feels too stretched out for one rider may be just not cramped for another, assuming about the same height for both.

For a definite answer you either have to try the bike out. Or compare the geometry of the bike with a bike you already know.