Can I use bash?

Yes, you can use it.
A login shell is set to csh by default on SX-ACE and VCC. How to change shell is the following.

$ bash

If you want to change login shell from csh to bash, please describe the following in ".cshrc" file on home directory.

exec bash

It is necessary to prepare ".bashrc" file by yourself When you set an alias to bash.
A login shell is set to bash by default on OCTOPUS.