Recent synthetic approaches to a series of [P₉]X salts (X = [F{Al(ORꜰ)₃}₂], [Al(ORꜰ)₄], and (Rꜰ = C(CF₃)₃); Ga₂Cl₇) overcome limitations in classical synthesis methods that proved unsuitable for phosphorus cations. These salts contain the homopolyatomic cation [P₉]⁺ via (I) oxidation of P₄ with NO[F{Al(ORꜰ)₃}₂], (II) the arene-stabilized Co(I) sandwich complex [Co(arene)₂][Al(ORꜰ)₄] [arene = ortho-difluorobenzene (o-DFB) and fluorobenzene (FB)], or (III) the reduction of [P₅Cl₂][Ga₂Cl₇] with Ga[Ga₂Cl₇] as Ga(I) source in the presence of P₄. Quantum chemical CCSD(T) calculations suggest that [P₉]⁺ formation from [Co(arene)2]⁺ occurs via the nido-type cluster [(o-DFB)CoP₄]⁺, which resembles the isoelectronic, elusive [P₅]⁺. Apparently, the nido-cation [P₅]⁺ forms intermediately in all reactions, particularly during the Ga(I)-induced reduction of [P₅Cl₂]⁺ and the subsequent pick up of P₄ to yield the final salt [P₉][Ga₂Cl₇]. The solid-state structure of [P₉][Ga₂Cl₇] reveals the anticipated D₂d-symmetric Zintl-type cage for the [P₉]⁺ cation. Our approaches show great potential to bring other [Pn]⁺ cations from the gas to the condensed phase.