Change your transmission fluid using the simple drain and fill process. Don't take it to a place that advertises "power flush." If you've been using the maintenance minder properly it should notify you to do it at around 60k miles (for the 9 speed). If you've been reseting maintenance minder early you may have thrown off the notification system.
Your dealer may be able to reset the maintenance minder to get you back on schedule.
Keep in mind, some shops/mechanics may say flush, but mean drain and fill. I've always found those terms to be used interchangeably. I've never encountered anyone who thinks power flushing transmissions is a good thing to do.
ATF drain and fill for the 9 speed can be as high as $300. The fluid is different than the 6 speed and still pretty expensive. I think College Hills Honda has it advertised for $25 per quart, which is probably less than your local dealer.