I've read all the books, and from the trailer and description, there is not much similarity with the film. from the books, the signs are that he is about 12, and this stuff about being fought over isn't in the books. the name of the film is ridiculous, the first book was called 'cirque du freak' and the second book, 'the vampires assistant'. The wider story arc which made the whole saga so great may be corrupted, especially considering all the subtle hints throughout the series that made it so interesting.
I realise the changes may be to spice it up and make it a better film, but I can't help thinking it will be like Eragon or Stormbreaker; good books, but horribly mutilated when made into films.