  We give necessary and sufficient conditions for a closed orientable
9-manifold M to admit an almost contact structure. The conditions are stated in
terms of the Stiefel-Whitney classes of M and other more subtle homotopy
invariants of M.
  By a fundamental result of Borman, Eliashberg and Murphy, M admits an almost
contact structure if and only if M admits an over-twisted contact structure.
Hence we give necessary and sufficient conditions for M to admit an
over-twisted contact structure and we prove that if N is another closed
9-manifold which is homotopy equivalent to M, then M admits an over-twisted
contact structure if and only if N does.
  In addition, for W_i(M) the i-th integral Stiefel-Whitney class of M, we
prove that if W_3(M) = 0 then W_7(M) = 0.
