Letim z viedne z medzi prstatim v Guangzhou cakanie 8h50min. Na let na Phu Quok. Mozem cestovat bez

No, you don't need a visa because you will be covered by 24 hours visa free transit. You could even apply for a 24 hours free entry permit upon your landing at Guangzhou airport to exit the airport for a short walk in the city. Anyway, exit permit, especially when the length of layover is relatively short is always dubious and decision about issuing is always upon discretion of immigration official.