Kyoto: Hozugawa river boat ride reservation

Hello I just booked my Sagano Romance train ticket and I plan to take the boat cruise back immediately. I read that you can reserve the ticket at Saga Torokko station as early as possible to get the closest boat trip as my train ride ends. Is there any guaranteed departure hour online reservation method?

I saw that there is Klook and KKday. But both of them seems to mean I "redeem" my ticket at the departure center (which is when I already finish the train ride) with no guarantee about riding hour.

I am starting from my trip from Osaka that day, so having to be at the ticket office (Saga Torokko station) at sharp 8:30am to earn my ticket is kinda rough. Is it a hot activity? Or can I leisurely show up before the train ride and reserve my boat ticket?