Get Odoo 9 running on OSX is quite simple with the Bitnami Odoo Local installer which can be found here.

The first problem is the missing wkhtmltopdf library which Odoo uses to create PDF documents (quote, invoice, etc.).
Using 0.12.3 worked fine for me.
The problem is that Odoo expects it in /usr/bin but it´s installed to /usr/local/bin and can´t be (simply) copied  as in recent OSX Version the /usr/bin dir is restricted.

You need to add a file setenv.sh to  <Odoo-install-dir>/apps/odoo/conf/

containing

export PATH=$PATH:/usr/local/bin

this tells Odoo to search for the wkhtmltopdf library in /usr/local/bin and Odoo prints PDFs finally.

With the Bitnami Package comes Python 1.7.10 which seems to have problems connecting to remote services through OAuth 2, e.g. Google Integration: https://github.com/asciimoo/searx/issues/120

Using pyenv installed with homebrew helped using 1.7.8 which finally solved the problem.