Haven’t started my journey and have dates 7/10 - 9/9 but already saying 1/10 used. Does anyone know what this means?

You have activated the pass for those dates so it automatically marks the first date selected as your 1/10.

You can deactivate the pass now and anytime up until midnight before the first day you have selected. Once that has passed it is active and cannot be subsequently deactivated.

Only when you are certain you are using it on the day should you activate it as you then have options should an unexpected event happen and you need to change plans or refund the pass.