British bookmaker William Hill opened its betting on the Kentucky Derby, installing Johannesburg as the 9-2 favorite. Repent is next at 6-1, followed by Siphonic at 7-1.William Hill, which also opened its future book betting on the Hong Kong Derby, has been taking Kentucky Derby bets for several years. "We have already had a lot of people backing Johannesburg for this year's Kentucky Derby over the last week," said William Hill public relations head David Hood, "and if money talks, then the (Aidan) O'Brien camp must already have booked their flights. Johannesburg looked special in New York last year and punters reckon he could be the one to steal the Derby away."Other Derby odds are: Came Home, 10-1 Saarland, 12-1, Harlans Holiday and Booklet 14-1, Tempera, Saratoga Blues and Labamta Babe (injured) 16-1, Sunday Break, Request For Parole, Kings Consul, High Star, Easyfromthegitgo, Danthebluegrassman 25-1, USS Tinosa, Smooth Jazz, Nokoma, Janadel 30-1.