Questions about Musée de Cluny late hours on Thursdays

Hello! I will be in Paris with a friend in September; we will be there on the third Thursday of the month, so I'm wondering if we should take advantage of the Musée de Cluny extended hours. I'm looking for some specific information, but I haven't been able to find a detailed account online.

1. I'm a little confused by the website, it says that late night Thursday admission "can be done from 17:30". When I go to buy tickets for that date, I'm able to choose a reduced rate of €12, but it still shows at 9:30 for the only time option. Is this the correct selection, and the ticket will only be accepted after 17:30? Or am I looking in the wrong spot?

2. Are the Thursday evenings something we should book far in advance? Or could we decide on the day?

3. The website says Thursday evenings "also feature a dedicated cultural programme". Does anyone know what this means? My companion speaks no French, so I don't want to accidentally take her to a talk or something that she won't understand. I was also hoping we'd be able to just explore the museum on our own, not attend a special event.

Thanks in advance for any help! I am dyyying to see the unicorn tapestries (and so sad I'm missing the special unicorn exhibit), so I will be going one way or another! But I'm hoping Thursday evening will be a good option for us as we already have a packed itinerary!