Full years can be contracted to two digits like
He graduated the university in '92.
What I'd like to ask is how would this sentence be spelled out:
- "in 'ninety two"?
- "in ninety two"?
- maybe, it's pronounced and spelled some other way?
Apostrophes are normally used to indicate omitted letters or digits rather than whole words, and the modern tendency is to avoid initial apostrophes anyway. Therefore, I recommend spelling out the year without an apostrophe (and the few examples I could find concur). Note the hyphen:
He graduated in ninety-two.
For the first decade of the century, I recommend spelling out zero as oh or aught, as commonly done in speech:
She graduated in oh-seven.
I would not recommend spelling out years from the present decade in this way, especially for the years 2010–2012. In speech, people tend to say twenty-ten rather than ten, and they may not even realize that you're referring to a year if you write the latter.
We do sometimes use apostrophes for exceptional cases where the usual conventions would be awkward or ambiguous. Therefore, you may want to use an apostrophe for the teen years to help signal that you're writing a year and not a number:
They graduated in ’thirteen.