[Guido]

I really can't actually say if episode 9 was whether a filler or not.

It displayed casually much about Sei's present, and the tribulations she will have to endure as the next heir of the "Bai-Lan" clan (White Orchid).

This episode was really rich in Chinese folklore and background history plus we could appreciated some wacky kung-fu action.

Sei, Amy, and Meg's Chinese dresses were fashionable and gorgeous; Amy's was kawaii, indeed.

As for Jo, good riddance that she did not wanted to assist that formal party. I can't picture Jo wearing those flamboyant Chinese clothes or any other fashionable garments, after seeing her in those school robes back in episodes 5 and 6.
Probably, Jo has to endure in coming up with dressing and make-up when the mission requires any kind of formal activity involved just as it was the case in episodes 5 and 6. However, since the "dragon party" in this episode 9 has nothing to do with an official mission, she didn't had to.

We got to know some of Jo's preference for her profile in this episode:

Spoiler:

-She likes any kind of B-horror flicks saturated with gun-fighting and extreme graphic violence.

-Jo can become caring for strangers who managed to gain her respect, therefore, becoming friends.
She offered some her potato chips to Kyouhei knowing that he was hungry.

-It's the first time that she addressed Kyouhei by his name.

-Baddies should learn that under any circumstance they should never beat or mistreat Meg, or else Jo will going to make them pay for it.

-BTEOE, she commented Kyouhei that Sei's going to pay all damages to his scooter.

As for the rest of action in the Dragon Cruiser, that old Chinese man is the ultimate Kung-Fu master.

Spoiler:

He released Meg Chi's flow and mixed it with some of his own, thus producing the ultimate Kung-Fu combatant.

This clearly demonstrate the conquest of Sprituality against Technological enhancement, because Amy freaked out at Meg's enhanced strength and could not believe that Meg attained those mystical powers without nano-chips.

GONZO has really reversed the male and female roles in this show.

Spoiler:

-The three girls attend a formal, business party while Kyouhei stays home cleaning.
-No joking, but it's the first time I see in an all female-protagonic anime that the girls are calling idiots one to the other and beating among themselves due to stupid commentaries or deeds. No loser or nice, wimpy guys were beaten or called idiots during the making of this episode.
Meg kept on beating Amy on the head due to her annoying commentaries about she was flirting with the Chinese man.

We now know some interesting facts for Meg's profile.

Spoiler:

-Meg cannot moderate herself when it comes to exotic food, she has not yet tasted.
-Meg oh sure likes handsome guys, as along as they do not play for the enemy team.
-Her Chinese outfit was sexy but not provocative.
-Her stomach is where all of her Chi concentrates and flows in and out of her body. When released, she turnes into the winged, white Tiger Goddess (Byakko of the West)

For anyone who didn't realize about the cultural and folkloric aspects of the place and the guests clothes, have you figured out that Sei's name likely comes from Seiryuu.
One of the four holy beasts that guard the Earthly, cardinal directions. In Far-Eastern mythology, Seiryuu is the blue dragon of thunder which guards the river of the East.

That's why the name for this episode, "Dragon Party".