Captivate 9 -Why would caption text not display in film strips?

Not the filmstrip then. Now you tell something different: you say that the 'text' is not appearing, but the caption box appears? Maybe they are filled with a script? Can you check the Advanced Interaction panel (F9) to see if the On Enter events of the slides are triggering something? I don't see a placeholder for a variable, which means it is not done with an Advanced Action, but could be done in another way (JS?)

Are you talking about the 'Filmstrip' or the stage? What Christopher shows is making the objects on the Stage invisible, but they will always be visible in the Filmstrip. That should also never have any effect on a Preview, this functionality of hiding objects on the stage is only for editing reasons when you have a lot of objects covering each other on the Stage. As I mentioned this eye button has no effect on the Preview nor on the Published version. If you really don't see an object in Preview (real Preview, not the Play Slide) you have to check the eye icon in the top left of the Properties panel: if that eye icon has a a diagonal line the object will be invisible in Output, which means both in Preview and after Publishing.