The ten hole Hohner "Golden Melody" has been revolutionized by Howard Levy with the use of overblows enabling it to play chromatic notes by filing the reeds. A "Golden Melody" might be a good start so that an 8 year old could grow into this kind of versatility.

It's really hard to bend notes on a chromatic and its use is limited to certain areas such as Toots Thielmann's jazz or Larry Adler's classical.

Eventually a good harmonica player can handle different styles of the instrument as was done in harmonica bands such as the Harmonicats or Borah Minevich, which can be accessed on YouTube. A real harmonica player can handle all types, chromatic button, 10 holes, bass harmonica, echo harps et. al.

For a real professional harmonica player you might want to look up Tommy Morgan who did a lot of the studio work in L.A. for movie tracks.