'The Ninth Gate' is an instant classic, a tasteful, idiosyncratic, and tactfully executed film on the occult knowledge so many know nothing of, a film of powerful symbology.
This film is an ode to the uninitiated, demonstrating how the occult world and its knowledge is more commonplace and 'real' than we might believe, it surrounds us, it is us.
At all times, 'The Ninth Gate' makes the viewer question its directions and motives, even the lead character, Corso (Johnny Depp), cannot be trusted, everything is expendable, with a lingeringly somber feeling of danger and fragility at every twist and turn.
Corso comes from the Latin 'cursus' meaning 'course'; the events that unfold become a prophesy that Corso is on a 'course' to fulfill from the very start, this is a reference to the left and right hand paths and how our choices affect everything, Corso chose marriage with the covenant of Satan, The Girl (Emmanuelle Seigner), the antilight.
9 is the number of Satan, the number of base consciousness, the ego.
In the Satanic Rituals (THE UNKNOWN KNOWN) Anton LaVey speaks ambiguously and enigmatically about the number 9 being the main number of which to identify with Satan and the ego.
"Despite other's attempts to identify a certain number with Satan (meaning 666), It will be known that Nine is his number. Nine is the number of the Ego, for it always returns to itself. No matter what is done through the most complex multiplication of Nine by any other number, in the final equation nine alone will stand forth." - Anton LaVey, The Satanic Rituals
The number 9 also refers to Yesod node of the tree of life, Yesod channels, the feminine Malkuth receives (sex act, as in the film). In turn, it is through Malkuth that the earth is able to interact with the divinity. This may be what is portrayed in the events detailed in the film.
'The Ninth Gate' is one of Roman Polanski's greatest works, threading together an engaging psychological thriller with a philosophical and theological backing that keeps the whole piece held in an air of mystery and suspense.
The sets are Gothic and gloomy, the music is aptly fitting, the acting and scripts even more so; nothing breaks the persistent, unshakable scene and tone that is set by Polanski, who has obviously taken into careful consideration every possible factor to create a deeply immersive, memorable experience for the viewer.