Here's my problam:
I'm a DM to a party of 6 PCs +1 NPC, all of levels 3-4.
Due to an unforseen incident (one of the PCs got cocky for having a holy artifact-weapon of Lathander at his temple at Evening Star) 2 extra 1st level paladin NPCs are accompanying the group on their adventures, protecting the "Wielder".
So what we have here is a group of NINE characters wading their way through adventuring career.

The problam is that I'm running "The Sunless Citadel", an adventure aimed for a group of four 1st level PCs. They're 9 with an average level of 2.7! Not to mention the sorcerer's cat familiar and Meepo, a plot specific NPC kobold.

Of course I revamped the monsters, making the goblins tougher and slightly more numerous, changed the druid to a lich, etc.

BUT, still, in a group of 9 characters, one has a real problem to stick out and most of the players are feeling, well, over-crowded. It takes most of the combat to roll for initiative for everyone, then only 2-3 rounds for every monster to die. I tried sending a young-adult dragon at them (the mother of the infant dragon the kobolds stole, if you know the adventure) and THEY KILLED HER with NO CASUALTIES.

Help! How can I get rid of the access NPCs without making it seem too contrived, plus how can you make an adventure more fitting to 9 players.

Any ideas are welcome.