The first time when I drove was at driving school.
consists of the subject "the first time when I drove" (a noun phrase referring to a past event), the copula "was", and the subject complement "at driving school" (an adverbial phrase describing a time and/or a place). That is to say, it has the same overall structure as, say, the following sentences:
The box was on the table.
The party was at John's house.
My birthday was last week.
The subject "the first time when I drove" is probably best analyzed as a single unit — specifically, as an instance of the idiomatic pattern "the [ordinal] time (when) [something happens]", as in:
the second time (when) Alice rode a bicycle
the next time (when) I go to France
the last time (when) it rained here
(In all these phrases, the word "when" is optional; the choice whether to use it or not is a matter of personal preference. I would usually omit it, since I find that to sound more natural, but sometimes including it can reduce ambiguity.)
What about your sentence, then?
** Dracula when I saw was the latest/last movie.
This sentence would seem to have the same overall subject–copula–complement structure as above. However, the putative subject, "Dracula when I saw", is not a meaningful or even a syntactically valid noun phrase, so the sentence is not grammatical.
When you meant to write, as suggested by oerkelens in their answer, is presumably something like:
Dracula, when I saw it, was the latest movie.
When I saw it, Dracula was the latest movie.
Dracula was the latest movie when I saw it.
In all of these sentences, the subject (of the main clause) is simply "Dracula". The dependent clause "when I saw it" is not a part of the subject here, but simply augments the entire sentence to indicate that it applies to a specific time in the past.
Note that the word "it" within this dependent clause is required, since the verb "saw" normally requires a direct object. Here, this object is the same as the subject of the main clause ("Dracula"), so we can simply refer to it using the pronoun "it". Of course, one could also write, say:
* When I saw Dracula, Dracula was the latest movie.
but such repetition sounds very awkward, and should normally be avoided.
As for whether to use "latest" or "last" here, I would use "latest", since it specifically means "newest" or "most recent", which is presumably the sense you intended here.
The problem with using "last" here is that it leaves the sentence ambiguous — it doesn't specify of which set of movies Dracula was the last one. Some plausible ways to continue the sentence, in order to make it unambiguous, might include:
...the last movie shown that day.
...the last movie I watched before going home.
...the last movie released that year.
Alas, none of those really match your (presumably) intended meaning, although the last one comes close. You could say something like:
* When I saw it, Dracula was the last movie released so far.
but, while understandable, using "last" like that (referring to a time interval that ends at the time being described) doesn't really sound correct to my ear. It would be much better to replace it with, say, "newest" or "most recent" or, indeed, "latest".