Does the Psion have an equivalent power to the spell Murderous Command? I can't find one.
The closest I’m aware of is death urge, which is suicidal rather than homicidal, and much higher-level to boot, but also demands more of the target than just a single attack. Ultimately, most psionic powers in Pathfinder are either ports of powers from the 3.5 Expanded Psionics Handbook (2004, Wizards of the Coast), which was much before murderous command (Ultimate Magic, 2011, Paizo), or original creations by Dreamscarred Press.
Generally, thematically-fitting spells can be made into powers and vice versa without problems. There are certain things that each does that the other doesn’t, or at least doesn’t do as well (and I can go on at length about those), and I think those are important distinctions to maintain, but there is also much overlap. Murderous command is as fitting as a telepathy power as it is as an enchantment spell.
On the other hand, one reason to be cautious in porting spells to powers is that spells are often poorly balanced, and I would argue that murderous command is much, much too good for its level. I don’t like it as a 1st-level power—precisely because I don’t like it as a 1st-level spell.