I've played a fair bit of Advanced Civ (and Civ before it) over the years, but I think yesterday was my first eight-player game.
We actually had nine people (and were going to play other games), but one of the people was feeling fuzzy-brained and didn't want to play a long game, opting instead to team up with a partner (which was fine). Of the nine, three had not played before and one had played only once (but that one picks up games really quickly so doesn't really count). It went pretty well anyway -- my previous thinking had been that Civ can accommodate up to two new players at a time without descending into chaos, but this worked. It helped that all the experienced players were willing to help support the newer ones and that we played a fairly friendly game.
That was one of the surprises, actually -- with eight players I expect a crowded board, so I had anticipated a lot more conflict. We didn't have much, probably because the calamaties knocked people down before other players could do so more directly. :-) (With that many players you're getting half a dozen calamities per turn once things get going. Some of the calamities can be traded, so you can try to target the front-runners.)
Predictably, we had all positions in play except, err, orange -- I forget what civilization that's supposed to be, but in our group it is widely believed to be the weakest position on the board. I played Illyria, which I haven't done in a while, and had friendlier relations with my neighbors Thrace, Iberia, and Crete than I expected. I never got up to nine cities; Illyria is definitely challenged for suitable city sites (I think Crete usually grabs a couple that I grabbed), but it's also true that most players never got to nine cities. Egypt and Assyria did, and I think Babylon did once. Cities came and went at a higher rate than usual because of the calamities.
Amusing geography: due to civil wars we had Cretans in the Nile basin, one Assyrian city on the plains between Illyria and Iberia, and Illyrians in Africa. Also barbarians in Iberia and Babylon -- we managed to give the barbarian hordes to Crete (who is immune) a few times.
We ended the game a few turns early (someone had to leave); we all thought Egypt was far and ahead the winner, but in fact he beat Assyria by only 20 points. Hmm, sneaky Assyrians. :-) I was fourth, I think. One thing I like about (Advanced) Civ is that it can still be a lot of fun even if you're not in the running for the top spot.