I do not know whether the best translation of the entire passage allows that variation. Most translations I’ve looked at do say “stood there” or “stood by”. But that may only show that the translator chose to preserve the ambiguity of the Greek by translating it into ambiguous English. Preserving the ambiguity of the original is a very sound translational principle, so it would not surprise me to find multiple translators making the same move.

Response 2: Let us assume that some of the men Luke refers to in Acts 9 _were_ standing. Notice still that in the one case, it is Paul-and-his-companions that fall to the ground (in Paul’s report in Acts 9). In the other case, it is the men-traveling-with-him who are standing (in Luke’s description in Acts 26). Paul may have been traveling with a small group of associates and servants in a much larger caravan of people.

Now suppose that the entire caravan stops when the men in it hear the voice from heaven and see the light shining around Paul and his few companions. The men surrounded by light fall to the ground, but the other travelers stand amazed.

So it might be that all that is happening here is that in his account to Agrippa Paul mentions himself and his few companions. In Luke’s description of the event, he mentions the large company of men traveling with Paul’s little group.

If I were an inerrantist, though, then I wouldn’t want to rely on this too often. For one thing, Paul will start to look less credible if he can’t even get the details of his own conversion correct.