Grammar allows several possibilities. This is for a purpose, as this allows one to express nuances of meaning. The rule of thumb is that when different orders of words are possible, whichever word comes first gets the emphasis.
The phrase:
pursue other passions than just diving
stresses (semantically) the idea that the person had a shift in their passions. Whereas:
pursue passions other than just diving
emphasizes that the person is still passionate, but has found other outlets. Note that this one sounds more formal.
Playing around with the order of words or clauses in a sentence can be very useful when writing, e.g.:
He had, that way, more time to pursue other passions than just diving.
Bringing he in front could better express the thought of the writer, if their focus of attention was on the character rather than on the method.
Of course, some forms are more usual than other in different places (dialects) and contexts (legal, academic, etc.); but on occasion, deliberately shifting the order of words or clauses can achieve a stylistic effect or dramatically simplify the sentence.
The bottom line is that grammar and usage rules are not all on the same level. Some are mandatory, others are prevalent; this leeway is something that writers or speakers can use to their profit, when they want to create a particular effect or nuance.