Your loss, at any rate in terms of relaxation. For it is a holiday not a military exercise. I would wander off the ship, with a map, and probably see most of the same things. I must say I should certainly like to visit Zadar.
I think London to Barcelona in a day via Eurostar is pretty brilliant, if you are able to do it. As is Southampton to Nîmes without going to Paris. They have stated at the start that flying is not an option. So there we are.
The man in Seat 61 mentions changing at Lille for an overnight in Nîmes, enabling you to avoid Paris altogether. This leaves St. P at a doable 13.01.
https://www.seat61.com/Spain.htm#London_to_Barcelona_with_overnight_stop_in_Nimes
Lucky old you. We are on again next month, hopefully without the benefit of Covid.
As there is another thread about this, do let us know what the party position is, even if you don’t attend.
How was embarkation?
I think it will be vastly easier to get between stations in Paris in an hour than to get to St. P by 9.26. I still think 10.26 is cutting it very fine, but it being on a Sunday should help. In any case you are very brave.
Passport checks are done on board TAs. It is customs checks than can hold you up, but only quite rarely. Often there is nobody there.
In any case Pushpit has effectively demonstrated how unlikely it is you will catch the 9.24.
I would plan for a night in Paris. What day of the week is it? You will get into Central London very quickly on a Sunday, while, say, a Thursday morning rush hour could be very slow.
If they do manage to move to a system with no auto gratuities on top of the fare, and no expectation of tips, I’m sure many of us would welcome that, providing the staff don’t ultimately lose out.
I would say that in the last view voyages before Covid, these events, such as they are, were spoilt for me by the surprisingly large number of passengers who continued to talk quite loudly during the Captain’s address. This seemed very rude.