Is it ok to hang a ceiling fan from an Iberville Octagonal Box 1-1/2 Inch AC90 Steel Stud?
Nothing in the box itself, nor any of it sales literature, indicates that it’s fan-rated.  If it were, they’d be shouting that pretty loudly, because it’s a major feature.
Fan-rated boxes are special
Because fans are not a static load.  A 30-pound chandelier just hangs there.  A 30-pound fan vibrates and shakes.  These dynamic forces are what make ceiling fan boxes so critical/tough.
If you install a ceiling fan on a non-fan-rated box, it is likely to cause fatigue failure in the box or fasteners, and drop a spinning fan on somebody’s head.