33.

12345678910
Across
  1. 2. Ogdoad
  2. 5. Eight's follower, CB Radio style
  3. 7. Nine-minus-eight's sum
  4. 8. Octad parts
  5. 10. Niner Eighter = Er, what?
Down
  1. 1. Last in Henley, German eight's boat
  2. 3. Octad in a gallon
  3. 4. Old number eight's heel on loose footwear (3,3,3)
  4. 6. Octad plus one
  5. 9. Eight's cube root