Those temperatures aren't a problem.
While the CPU may idle at under 30°C, within a second, once a load is put on a CPU, it will jump up. Even if you set the fan speed to max, it will run no cooler. The issue is that CPU cores have such small surface area now that they can't dissipate heat quickly enough to the heatspreader, and then to the heatsink. Newer CPUs will thermally protect themselves once they reach around 100-102°C. My 6700K will jump from 26°C to 65°C within a split second if I launch just about anything, and creep up to 70°C+, with a large tower cooler that stays cool.
Below 90°C with a higher ambient temperature, you're fine. I prefer not seeing higher than 80°C just because traditionally that has been very high. Many laptops allow their processors to run above 80°C before running at max fan speed.