The seven categories I identified—the list is reproduced below—follow a trajectory from melodic to harmonic; that is, the ninth as a plainly melodic feature (1.0 and 1.1) to the presentation of V9 as a harmony with a direct resolution of the ninth into the fifth of the tonic triad or into ^6 over the tonic (2.3). I don't pretend that these categories have cleanly defined "edges" and are therefore ready labels for any possible example. Instead, they are better thought of as ranges on a continuum whose points would represent individual instances in the repertoire of 19th century music. The examples below the list illustrate.
1. Internal resolution (within the V chord)
1.0. Element of melodic shape (step)
1.1. Element of melodic shape (leap, off the beat)
1.2. Element of chord, weak beat
1.3. Element of chord, strong beat
2. External resolution (to the following chord, usually I)
2.1. Indirect resolution to ^5
2.2. Indirect resolution to ^6
2.3. Direct resolution to ^5 or ^6
A first set of examples for the seven categories above:
1. Internal resolution (within the V chord)
1.0. Element of melodic shape (step)
1-0_Mozart_German Dances, K600n1trio. String parts only. Simple passing tones.
1-0_Mozart_German Dances, K605n3. String parts only. Simple passing tones, but on the beat. No effect on the underlying harmony.
1.1. Element of melodic shape (leap, off the beat)
1-1_Schubert, D779n5. The leap hints at arpeggiation -- more than hints in this context, where fifth leaps are ubiquitous. Although ^6 resolves immediately in bar 7, in bar 3 one hears it more easily as a delayed resolution to the next bar (category 2.1) and thus the entire bar could be regarded as a V9 harmony.
1.2. Element of chord, weak beat
1-2_Johann Strauss jr_op7 n1. The decorative "Laendler leap" dominates the melody here (see bars 2-4 and bar 8) and thus it is not a surprise to hear it in bar 6 as well, going past B5 to C#6.
1-3_Josef Lanner_Pesther Walzer, op.093_n2. Here the sound of the dominant ninth is strong, but so is the figure of the appoggiatura/incomplete neighbor. I would not label bar two, in part or whole, as a V9. On the same grounds, I would not read bar 5 as Iadd6. Notice at the end consequences of the expressive lifts throughout the strain: an ascending figure in the cadence.
2. External resolution (to the following chord, usually I)
2.1. Indirect resolution to ^5
2-1_Johann Strauss, jr_polka_op236, trio. One of the clearest examples of this figure I could find.
2-2_Schubert, D365_n1. The ^6 in bar 3 links back to and confirms the significance of ^6 on the strong beat of bar 1. In this case, I could hear bars 1 & 2 as Ab: V9.
The opening of the Act II Prelude in Wagner's Tannhäuser. No doubt about this one!
As the two Schubert examples show, it is by no means uncommon to repeat ^6 at the moment of tonic resolution, in order to create a link back to the ninth of the V9 chord. Here it is in the third waltz from Johann Strauss, jr.'s Künstlerleben [Artist's Life], op. 316.
Reference: Richard Beyer, "Bemerkungen zu den Nonenakkord," Musiktheorie 11/2 (1996): 91-110. Page 102 for the Tannhäuser example.
