At least your CPU is locked, but remember, the 100ºC Tjunction is not to use as a limit. This is the auto-shutdown so that your chip does not fry, let’s say if your fan goes bad or if your water cooler pump fails. But Tjunction is not to be considered in 24/7 use.
You have to maintain the CPU below the max Tcase, which on Intel hovers around 75/80ºC on the last generations if I’m not mistaken. That is, 24/7 operation. So if you let your CPU render a video for a couple hours, it is not advisable to go over the Tcase.
As a rule of thumb, 80ºC is the warning line, when you do need to start figuring out what’s happening with your CPU temps. Yes, some people reach 90ºC all the time and think it is fine… Until it is not fine anymore. I’ve seen a case of overclocking an i7-4790K, running a stability test at 90ºC and in the next day they could not achieve the same clock - in other words, the chip wore out in 24h.
High temps and chips are not a good mix. Always keep it in check. I reckon that temps are more dangerous in overclocking, but I would not bet on it.
What cooler are you using? What thermal paste? Since it is a locked i7 9th generation, you can buy a very inexpensive air cooler and a good thermal paste to fix the problem. I do have an i7-9700K and it has good temps, keeping around 70ºC in heavy rendering (South America, Brazil, so it is hot in here).
Also, if temps went overboard just recently, the tendency is that they will keep rising as time goes on. Something might be wrong or just deteriorating, like bad thermal paste or a mounting bracket going bad. So take care of it now before your rig starts to shut down due to high temps.
A decent Hyper 212 with MX4 should do the trick.