I had this issue come up in my last Starfinder game. I usually let the players do it for free, but in this session, there was a creature on a planet that no one from the Pact worlds had visited in thousands of years. So I said standard Action but later went to look up the rule.
If it is a free action, then in Starfinder, it converts to Swift action. Page 500 of CRB. If it's a swift action, then he can't use it with a trick attack. Now, if it's "not an action at all," then nothing limits him from rolling 20 times other than me as a GM setting a limit.
I like to run 100% RAW.
I took this to Starfinder Society Discord. In Pathfinder 1E, it clearly says Knowledge checks are one roll. In Pathfinder 2E, it says it is an Action. Starfinder..nothing.
So in my game, we are going with the Pathfinder 1E rule that makes identify creatures a non-action, but you can only roll once. This way, the operative still can trick attack while using Alien Archive (EX) and doesn't have unlimited rolls in a single turn.