Depending upon how big the people are, you may be able to get 8 ppl in there. But I would suggest calling them for verification if they have any vehicles that can seat 8 ppl comfortably.
Last time they've upgraded me and gave me a Kia Sorento (I believe) which had 7-8 seats. I didn't use all the seats. But when I got the car I saw a couple of minivans. I think it depends mostly on availability at the day you arrive. Hope that could help you.
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