Honeycomb iridates have received much attention as candidates for the Kitaev quantum-spin-liquid ground state since the seminal work by Jackeli and Khaliullin. A key experimental challenge is to find materials dominated by Kitaev interaction and observe the putative topological and fractionalized excitations in these honeycomb iridates. Resonant Inelastic X-Ray Scattering (RIXS) has proven to be a powerful technique for investigating Kitaev honeycomb iridates, providing valuable insights into Kitaev quantum spin liquids and their magnetic phenomena. In this talk, I focus on low-energy excitations in Kitaev honeycomb iridates which are emergent collective excitations of spins in the Kitaev honeycomb lattice. RIXS response of magnetic excitations from ordered spins allows us to constrain the parameter regime of the extended Kitaev-Heisenberg model in the materials. At high temperatures, a broad RIXS response persists, indicating possible activated flux pair excitations. I also present attempts at obtaining the parallel polarization RIXS response using the scattered X-ray polarization analyzer, which exclusively probes the fractionalized excitations (Majorana fermions). Ultrafast engineering of a Kitaev iridate towards the Kitaev Quantum Spin Liquid using the strong interaction between ultrafast laser radiation and matter is a promising way to bridge the gap between the ideal Kitaev honeycomb lattice and the real materials with many other interactions than the Kitaev interaction. I present early results of the ultrafast pump-probe RIXS experiment at the X-ray free electron laser facility. I conclude my talk by discussing the upgraded Advanced Photon Source and its potential for advancing RIXS studies of Kitaev honeycomb iridates.