Compare Daniel’s vision in Daniel 10 with Luke’s account of Paul’s conversion/call on the Damascus Road:
Daniel 10:7 And I, Daniel, alone saw the vision, for the men who were with me did not see the vision; but a great terror fell upon them, so that they fled to hide themselves.
Acts 9:7 And the men who journeyed with him stood speechless, hearing a voice but seeing no one.
Acts 22:9 And those who were with me indeed saw the light and were afraid, but they did not hear the voice of Him who spoke to me.
In both Daniel and Acts, the prophetic figure sees a vision that those accompanying him do not fully comprehend.
Question: Is Daniel really a prophet? Though not a prophet in the classical tradition (like Isaiah, Jeremiah, Amos, etc.) the question is whether or not Daniel would have been perceived as a prophetic figure in the first century by someone like Luke. For Daniel’s inclusion among the esteemed spiritual heroes of Israel, alongside Noah and Job, in the exilic period see Ezekiel 14:14, 20; and 28:3.
Note: Those who seek "errors" in the Bible often see Acts 9:7 and 22:9 as being in contradiction, pointing out that 9:7 says Paul’s companions heard a voice but saw nothing, while 22:9 says they did not heard the voice that spoke to him. Is this is a contradiction? I do not think it is above resolution. In 9:7 the focus is on the fear of Paul’s companions to the point of losing their speech. Luke notes that they heard a voice but saw nothing. In 22:9, however, Paul says that his companions did not hear anything. The point of contention here may be two distinct uses of the verb "to hear" (akouo) in the two verses. The word "hear" can mean reception of sound or it can mean comprehension of intelligible speech. For example, I might hear someone speaking in a foreign language in the sense that my ears are receiving the audible sounds waves. This does not mean, however, that I hear in terms of comprehending and understanding what is being said. This distinction might easily be made in Acts 9:7 and 22:9 as well.
In addition, it is clear that Luke saw no contradiction in the two verses. Surely he would not have allowed such a glaring error to have remained in his text, if, in fact, there is such an error present.
Of course, the clear explanation for why Luke has Paul telling it this way (in 22:9) is, in fact, that this is exactly the way it happened and Luke faithfully has recorded the event. I believe that is true, but Luke also had to be judicious in what he chose by inspiration to write in Acts. He does not include all details, but he was inspired to include those most useful in achieving his overall literary purpose. Thus, it is not unimportant that Luke is led to portray Paul in the ways he does. Here is a thematic parallel, at least, to an event in the life of Daniel, that great OT figure, that Luke may have intended the LXX-saturated reader to understand.
Further question: Was it typical in Luke’s day to describe prophetic figures in circumstances where they are present with companions who are not able to perceive a spiritual experience as it takes place (a la both Daniel and Paul)? In this case Luke would not be modeling Paul on Daniel but on this typical prophetic experience in general.