All four of those expressions are common in American English and have the same meaning. Your use of “crave” seems a little off. We usually use “crave” to refer to something you have had previously, or have on a regular basis, and you want it now. Your meaning has to do with a wish for something new in the future, so I’d say something like “I wished for,” “desired,” “was dreaming of,” or maybe “I yearned for.” Your grammar is fine, although you may want to replace “when” with “while.” This would emphasize the on-going nature of your college studies. You may also want to change “went” to “was going,” for the same reason.

#1 is the one I like most. #2 implies implies that you wanted an IT job when you started college - but you may have changed during your time at school. #3 I would change that to "When I was in college" or "While I was in college" ("at college" sounds a little funny in American English. However "When I was at school" would be fine. No, it doesn't make sense.) #4 Again, I'd change that to "in college." Your use of "craved" is interesting. To me, that implies a deep hunger and desire, the type of want that occupies your every thought. If the only thing you cared about was getting a job in IT, (not friends, not other classes, not parties, not everything else that takes up time in college) it's the right word. Otherwise, I'd go with "wanted" or even "really wanted."

1. When I was attending college, I craved a job in the IT industry. (concurrent action; most correct) 2. When I went to college, (No. I would not use this phrasing.) 3. When I was at college, (same as #1) 4. When I was studying at college, (same as #1)

The first part of all four expressions are common and make what you are saying clear.

2. is clear and the rest are unnecessarily complex. A compromise wording: "When I attended college, I craved a job in the IT industry."