The crank pulley bolt has regular right hand threads (counter clockwise to
loosen).  You will either need a strong impact gun or a pulley holding tool if
you're trying to loosen it by hand.  If the '89 integra does not have the 50 mm
hex opening for the pulley holding tool (available at places like Tool Town),
then you can fabricate a tool to fit in the holes in the pulley.  Essentially,
you get a length of angle iron (about 2 feet or so) or other sturdy steel and
drill two holes in it.  For my '88 Civic I drilled the holes 3 inches apart.
This allowed the bolts inserted through the steel to lock into the holes
skipping a hole in between.  On my Civic the holes are 12 mm in diameter.  You
can use 12 mm bolts or you may have better luck using 7/16 inch bolts (11.11 mm)
as they will allow for a little margin of error with respect to the location of
the holes you drilled in the steel bar.  Try to use fine threaded bolts.  You
can even use some heat shrink tubing over the bolts to help protect the pulley.
Another option is to thread some nuts onto the bolts from the back side of the
pulley to help hold it but be sure not to over tighten them, just hand tight.

Another option which is less successful is to clamp an old alternator belt
around the pulley with vise grips.  You then clamp the other end to the
suspension.  Sometimes, if you're lucky, this works.  Other times, the belt just
breaks.  I personally think you'll be better off going with a pulley holding
tool.

Eric