Wedding Advice! Standing Ceremony?

As long as it's super short and you know that you don't have anyone with physical impairments, I think it's fine.

I'd also consider what will be happening before and after the ceremony. How far ahead of time will guests likely arrive? Where will they be able to wait? What circumstances might they encounter while waiting (e.g., could it be hot, cold, windy, rainy, etc.)? Then, what will they be doing immediately after the 8-minute ceremony? Are they going to need to continue to stand for the reception or will they immediately travel to another location for a reception that includes seating? While I always think it's better to ensure people have a place to sit, if they are literally going to drive up, park in a close parking lot, get out and stand for an 8 minute ceremony, and then get back in their car to travel to the reception, standing doesn't seem like a terrible idea. If it will be longer and/or more complicated than that I'd try to find a way to include chairs.

We would probably take pictures afterward which everyone invited would be involved in and then head to the reception after that. It is mostly just going to be our parents, siblings and a few close friends.

I think standing would be fine!

For a ceremony that short i think standing is just fine, I would just inform your guests that are coming that way the expectation is already set