A brief review of the essentials behind the construction of a Chern-Simons-like brane action from the Large $N$ limit of Exceptional Jordan Matrix Models paves the way to the construction of actions for membranes and $p$-branes moving in octonionic-spacetime backgrounds endowed with octonionic-valued metrics. The main result is that action of a membrane moving in spacetime backgrounds endowed with an octonionic-valued metric is not invariant under the usual diffeomorphisms of its world volume coordinates $ \sigma^a \rightarrow \sigma'^a (\sigma^b) $, but instead it is invariant under the rigid $ E_{ 6 ( - 26) } $ transformations which preserve the volume (cubic) form. The star-product deformations of octonionic $p$-branes follow. In particular, we focus on the octonionic membrane along with the phase space quantization methods developed by \cite{Szabo} within the context of Nonassociative Quantum Mechanics. We finalize with some concluding remarks on Double and Exceptional Field theories, Nonassociative Gravity and $A_\infty, L_\infty$ algebras.