Inital alphabet of 9, 1, 8, 6 and 3, arranged in that order.

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Across
  1. 4. Group with a common purpose
  2. 5. It’s fortune to have it
  3. 7. British ruler, often
  4. 8. Rodent-like pet
  5. 9. A type of dress
Down
  1. 1. Quick and nimble
  2. 2. Result of a process or calculation
  3. 3. Smash like Thor
  4. 6. I hated this subject