The paper presents a novel method for controlling and measuring a spin-7/2 system encoded in a superconducting transmon qudit. The authors utilize multi-frequency drives to generate rotations and projections in an effective spin-7/2 system by mapping it onto the energy eigenstates of a superconducting circuit. They implement single-shot readout of the 8 states using a multi-tone dispersive readout with an assignment fidelity of 88.3%. By leveraging the strong nonlinearity in a high $E_J/E_c$ transition, they simultaneously address each transition and realize a spin displacement operator. Combining this operator with a virtual SNAP gate, they achieve arbitrary single-qudit unitary operations in $\mathcal{O}(d)$ physical pulses, with gate fidelities ranging from 0.997 to 0.989 for virtual spins of size $j = 1$ to $j = 7/2$. These native qudit operations can be combined with entangling operations to explore qudit-based error correction or simulations of lattice gauge theories. The multi-frequency approach to qudit control and measurement can be extended to other physical platforms that realize a multi-level system coupled to a cavity, making it a building block for efficient qudit-based quantum computation and simulation.The paper presents a novel method for controlling and measuring a spin-7/2 system encoded in a superconducting transmon qudit. The authors utilize multi-frequency drives to generate rotations and projections in an effective spin-7/2 system by mapping it onto the energy eigenstates of a superconducting circuit. They implement single-shot readout of the 8 states using a multi-tone dispersive readout with an assignment fidelity of 88.3%. By leveraging the strong nonlinearity in a high $E_J/E_c$ transition, they simultaneously address each transition and realize a spin displacement operator. Combining this operator with a virtual SNAP gate, they achieve arbitrary single-qudit unitary operations in $\mathcal{O}(d)$ physical pulses, with gate fidelities ranging from 0.997 to 0.989 for virtual spins of size $j = 1$ to $j = 7/2$. These native qudit operations can be combined with entangling operations to explore qudit-based error correction or simulations of lattice gauge theories. The multi-frequency approach to qudit control and measurement can be extended to other physical platforms that realize a multi-level system coupled to a cavity, making it a building block for efficient qudit-based quantum computation and simulation.