Although not presented in the traditional "jigsaw" format, this is an "alphabetic" puzzle, in the sense that there is exactly one gird entry starting with each letter of the alphabet. If you'd like the jigsaw version, it is here.

Across:
   8. Generation briefly abandoned character in Bowie song who had light brown hair (6)
   9. Like a glass of vinegar in the rough endings, or unbearably sour beginnings (8)
  10. see 23dn
  11. It's worse to come back and experience a second time (6)
  12,13. Caledonian racer, dead keen gun, taking sharp corner hard (5 9)
  13. see 12
  16. Practices putting plants in containers for film (13)
  18. Subtle indication of turning carmine, not red? Nuances! (9)
  20. Ox has strange and difficult language (5)
  22. Sacrifice on behalf of identity (6)
  24. Those who've got it may go fast (8)
  25. Geese all contrived strange and difficult language (8)
  26. Animal has right body part (6)
Down:
   1. Inclination to write song (8)
   2. Excessive ration... dine extravagantly! (10)
   3. God's first in weed cultivation club (5)
   4. Ace prevents doom madly, and is excessively corrected (15)
   5. Animal housing harbouring listeria outbreak, as lacking hygiene (9)
   6. Volleyed up the middle getting wild audience response (4)
   7. It could secure bolts during vibration (6)
  14. Enhanced, heeding the problem (10)
  15. Special hooks lent visible features to timber panelling (9)
  17. Tiring, as siesta cut short with extreme of farting (8)
  19. Ring inserted into facial features, and neckties not favoured (6)
  21. In first part of promised land, criminal mob character dazed at being risen from the dead (5)
  23,10ac. Caledonian player excited anew by huge stadium, Roger returns (4 8)