Dean,
Sorry for the delayed response – I needed to try a few of these steps myself before giving you an answer. Do you have any idea why Twist will not work with 9.1? Is it an incompatibility with the base version of Eclipse being used or something in MyEclipse?
1) You can get 9.0 using the 9.0 offline installer, I can share the links with you. However, this will not give you the sharing experience you need.
2) I have created a custom feature that will lock your installation to 9.0, you need to add this to your profile along with another MyEclipse site that is publicly available. The feature is available as an archived update site (which you can host on your intranet if you wish or manually distribute to your developers)
Please write in to support@genuitec.com ATTN Brian with a link to this thread so we discuss further and so I can send you the required files.