Hello, i'm currently considering this offer to host a project using Phalcon.
Ssh access is provided, is this the only required thing to be able to install phalcon ?
That looks like a shared hosting with limitted ssh access. But maybe I am wrong. You will need to have a root ssh access. Better ask them before.
Why not buy a VPS? See this https://phalcon.io/en/hosting, for example in DigitalOcean plans start as low as $5
DigitalOcean is great $5/mo is a great deal.
If you really like OVH, they started offering VPS as well https://www.ovh.co.uk/vps/ (even less money than the offer you posted above).
You will have to KNOW how to install stuff using sudo apt-get, etc. (DevOps) and if you want use Chef, Puppet, Ansible or something simpler like fabric (I have example code for fabric at https://github.com/chrisgo/fabric-example)
My opinion:
Digital Ocean is great for testing technologies (NodeJs, Apache Nginx ...) as you can keep snapshots of your droplet (<=> VPS) and you are charged only the time your droplet is up. It also offers very nice tutorials (that you could apply to other offers).
But you have a better value with OVH for the same price, so I use it for on line websites.