The first part of Hilbert's sixteenth problem deals with the classification of the isotopy types realizable by real plane algebraic curves of given degree m. For m ≥ 8, one restricts the study to the case of the M -curves. For m = 9, the classification is still wide open. We say that an M -curve of degree 9 has a deep nest if it has a nest of depth 3. In the present paper, we prohibit 10 isotopy types with deep nest and no outer ovals.