One-Octonion Brane-Bulk Framework — Paper CCCXI: A Trail of Three Dark-Matter-Free Galaxies in the NGC 1052 Field — DF2, DF4, and now DF9 as Sump-Decohered Bullet-Dwarf Debris

Keim, van Dokkum, Shen, Danieli and Pasha (2026, ApJ 1004, 210; arXiv:2603.15860) measure the stellar kinematics of NGC 1052-DF9 with the Keck Cosmic Web Imager and find an intrinsic dispersion sigma = 6.5 (+3.9/-4.3) km/s - consistent with the stars-alone expectation (8.3 km/s) and far below the standard dark-matter-halo expectation (24 +/- 3 km/s). DF9 is the THIRD such object, after DF2 (6.3 km/s) and DF4 (7.8 km/s), strung along the same ~Mpc trail in the NGC 1052 group; a companion paper (arXiv:2606.05144) argues the trail formed in a high-velocity 'bullet-dwarf' collision. In the One-Octonion Brane-Bulk (OOB) framework there is no dark-matter particle: the apparent excess gravity is the sump, a coherent brane-current back-reaction whose strength is set by a0 = cH0/2pi and the T1/T2/T2* dephasing hierarchy (Papers XXVI-XXVIII, XXXIV). This paper is deliberately honest. All three galaxies are deep in the low-acceleration regime (Sigma_e = 3-8% of Sigma_sump = 238 Msun/pc^2; g_int ~ 0.6-1.2% a0), where a naive sump boost - like isolated deep-MOND - would predict sigma ~ 18-19 km/s, over-predicting the data by ~2.5-3x. The External-Field Effect cannot rescue this: g_ext = a0 only within ~12 kpc of NGC 1052 (its own T2* radius), whereas the members lie at 10^2-10^3 kpc where g_ext <~ 0.05 a0. The resolution is framework-specific and is the point of divergence from pure MOND: in a bullet-dwarf collision the sump's coherent response (T2*) is destroyed, so the second-generation tidal debris is sump-decohered - baryon-only dynamics that does NOT revert to deep-MOND when isolated and recovers toward the Radial Acceleration Relation only over a T1 ~ Hubble timescale. This yields a falsifiable prediction (register P104): dark-matter deficiency along the trail should anti-correlate with dynamical age. The three galaxies are reproduced, the bullet-dwarf reading is the one OOB needs, and the no-particle ontology is favored over both LCDM halos and isolated MOND. Honest status: the bare result is a tension (not a parameter-free win) resolved only through the still-qualitative decoherence channel, which rests on the bullet-dwarf origin being correct; surface density alone predicts the opposite (deep regime => more boost). Zero new free parameters. Verification script bundled, 8/8 PASS.