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

Across:
   8. Contest of a couple of pints against love? (6)
   9. Path able to be reconstructed in sequence of letters (8)
  10. State of cramp cured with oil (8)
  11. Afghans perhaps first to hear new sound (6)
  12,6dn. Maid aunt upset about end of traditional name for 24 state (5 4)
  13. Reisigning after King captured knight... rotten luck! (9)
  16. Nostalgic henna inscription shows where 9 CEO is from (7)
  17. Leninist Leyland, a vehicle for turning first Russian president (7)
  20. Perhaps Leylands, with exhibition including first of Ladas, regularly urge trust (9)
  22,23dn. 12 6 sports team on-court actions winning bonus (5 5)
  24. Oddly mean, Durban's a city now known as 16 (6)
  26. Noisily sought one's attention, as a nag will? (8)
  27. Light thrown into corners of mountain country (8)
  28. Fancy wine of good variety (6)
Down:
   1. After turning strange hue, actor was actively offered help  (8)
   2. Type of distillation of ground canola, first to remove source of smell (10)
   3. Loopback network measurement specific to area (5)
   4. Benjamin endlessly baffled about second source of smell (7)
   5. Tragic dupe, Charlie was taken in and lost his lunch in the States (9)
   6. see 12 across
   7. Whenever Dunkirk mentioned, earlier battle recalled by many (6)
  14. Haiti annul direction from Europe (10)
  15. One might advocate using ferret, sir: rabbits thereby brought up (9)
  18. Crack, cigs, beer... these things might sink you (8)
  19. Healer possessed, lost, at sea (7)
  21. Brief festivals of sex taking American uncle back (6)
  23. see 22 across
  25. Dare to change interpretation (4)