To add a bit: because TMM is a microkernel it'll occupy CPU - it's got real time priority (you'll see it as RT in the priority column in top). As a result it'll sit on idle cycles or has first right of refusal at the very least.I've not spent cozy time with 9.x for a good long while, but I do remember that TMM typically ran hot. TMM sitting on 40% CPU in 9.x doesn't sound alarming to me, for what it's worth. On a 10.x system it's common to see it sitting at around 8-11% utilization per core.
Despite all that, Aaron's advice is good, as usual - I'd open a case here too just to be sure.
-Matt