How can I defeat two freaking dragons simultaneously? My henchman becomes impacted by their fear and he soon dies. I have a 9th lvl thief / 7th wiz. Any strategies ya'll suggest?

Easy enough - use the Stone of Recall as much as you need to. ;)

As a rogue the first thing I'd try is liberal use of traps. Always seems to do wonders in softening up big foes. Might be kinda hard in the NWN OC if you haven't been concentrating on gathering traps throughout the game though. They're a bit trickier to come by in original NWN

Give your henchman potion of aid, its supposed to make a coward brave. and then try bigbys interposing hand on the dragons,that will at least reduce their attacks by -10, if THAT doesn't work, mordenkainen's sword has saved my tail a couple times, and yes, the stone of recall. the best bonus of the game.