you're all wrong. There's no such thing as a "bad" episode, so there can be no worst one, just some are less brilliant than others
We've been so spoiled by fantastic stuff over the last couple of years (the cheap car challenges, the Lotus vs helicopter, the cars vs trains/planes/boats) that you we think that anything that isn't brilliant is automatically crap
I'd say season 9 was different , but not worse because of that. And yes, the episode with the rocket Reliant did feel like it was missing something. But we had lots of excellent stuff to make up for that : the convertible people carrier, the epic American adventure, the "turn your car into a boat" stuff etc
I think they're just beginning to run out of ideas, they've done pretty much all of the fun challenges, now they've converted their cars into almost everything...what else CAN they do?