How can this kind of confusion about taxi instructions occur? A few days ago, I (a student pilot on a solo) had landed on runway 9 for a full stop taxi back. The taxi instructions were "alpha to 27 remain on this frequency". I missed some words in between these instructions, but after responding "alpha to 27" there were no corrections, so I continued my taxi to 27. At this point I should have asked for clarification. A jet was landing and I was blocking the exit as I had taxied and was holding short of 27. ATC responded saying I was at the approach end of 27 and instructed me to do a 180 and taxi to runway 9 (they were very nice about it though).

I've been racking my brain trying to think what those missing words were. I can't imagine they'd have said departure end of 27 instead of just 9. This may be one of those moments I'll never figure out, but would anyone more experienced have any idea what might have happened?

Unfortunately the airport is not on LiveATC.net and my GoPro died from low battery so this is all from memory.
I continue my series of "not actually an answer but I got to say this":

The most valuable lesson you can learn from this is not figuring out afterwards what was said, but getting into a habit of always asking "Say again..." when you miss even a slightest part of a transmission. Ron stated it in the comments: no shame in that, not even a bit.

Whenever you allow yourself to guess the missing parts, you put yourself, and probably others in danger. Requesting repetition, every now and then you'll catch the grumpy controller that'll bitch at you for not paying attention, but never mind them. You don't want extra holes in your Swiss cheese.