To install 9.0.1 on your box, run

./install.sh -v 9.0.1 -p [port your 9.0.1 server will listen on]

e.g

./install.sh -v 9.0.1 -p 15432

This will create a 9.0.1 runner script

~postgres/9.0.1.sh

So you can interact w/ your 9.0.1 environment like this

~postgres/9.0.1.sh createdb blah

etc.

To set XTRA Config Options:

env PGCONFIG_OPTIONS='--with-some-other-stuff' ./install.sh -v 9.0.1 -p 15432