If...
it was shifting through all 9 gears before the adjustment then the rd is probably 9 spd compatible. Chances are, you probably adjusted too much slack into the rd (you can check this by seeing if there is an extra click even after you shift to the highest gear). Take up all the slack from the cable and try readjusting.
If this is a new rd, the stops maybe misadjusted. You can download the installation manual for XT from Shimano's sight. Relatively easy to follow.
Good luck.
it was shifting through all 9 gears before the adjustment then the rd is probably 9 spd compatible. Chances are, you probably adjusted too much slack into the rd (you can check this by seeing if there is an extra click even after you shift to the highest gear). Take up all the slack from the cable and try readjusting.
If this is a new rd, the stops maybe misadjusted. You can download the installation manual for XT from Shimano's sight. Relatively easy to follow.
Good luck.