I took the ferry to Gulangyu with a small suitcase and learned that the ticket time is only part of the planning. The security queue moved quickly, but the pedestrian flow around the pier was slow because many people were taking photos and waiting for friends near the entrance. With luggage, that extra crowding matters.
Buying the ticket online was easy with a passport number, and the staff checked the passport against the booking before security. I arrived forty minutes before departure and felt comfortable, but thirty minutes would have been tight with the suitcase. On the return trip, the line formed earlier than I expected because people wanted seats together.
For anyone visiting on a weekend, I would plan a wider buffer and avoid carrying more than one rolling bag. Are weekday mornings noticeably calmer, or is the pier busy most of the time now?