How far is Xiamen Gaoqi International Airport to Ferry Terminal (ferry to Jinmen)?

The ferry terminal is usually called Dongdu Ferry Terminal (??), officially named as International Ferry Terminal. From Xiamen Airport, you could take a taxi to get there in 30 minutes. Of course, you could bring luggage on board.
You are exempted from visa to Jinmen.

Jenna, thank you very much for your information. Please may i know how much will it cost to take a taxi from airpot to the ferry terminal?

The taxi fare from airport to this ferry terminal is about CNY40 .

Jenna, do all taxi go by meter charges or i need to check price before boarding?
Any idea taxes or auxiliary travel charges upon departure is required?
Thanks

Some drivers may refuse to charge by meter at the airport, so you should check the price before boarding on. This situation is usual at airports in China.

Thanks Sophie. Can i assume the journey is about 20 - 30 mins from airport to Dongdu Ferry Terminal & fare will be around CNY40 - 60?

Yes, your understanding is right on the journey and cost.