At this point in the game, no. Zero is inaccessible due to the two splitting up and taking separate paths to fight Berkana and Gareth individually. (I'm playing in X Mode, not Hard/Complete Mode.)
Edit: .......... Well, [tornado fang]. You know that jump I was whining about? Apparently, it
is possible. You have to scroll the screen over a little to
activate the sprite object to scroll within your jumping range, but once you do, you can totally dash-jump to make that jump.
Without the dash boots.... well. I feel like an absolute fool now.
Edit 2: However... The next section after that is, in fact, physically impossible to get through without the Dash Boots. Unless you have a Bone Batton handy and have "
Xtremely" good reflexes. Hurr hurr hurr. ... Damn it.
Edit 3: Actually, nope.
It's still impossible. So
hah, I was right the first time! Just... I wasn't right about the
location. x: