While 40 db of phono stage gain is in typical situations inadequate for a 0.28 mv cartridge, in this case you will have enough gain, due to the unusually high gain of the preamp's line stage (selectable to either 30 or 36 db).
However, an ambiguity in the specs leaves me not completely certain as to whether you will have adequately low hiss levels, although I suspect that will be ok too.
Did you mean "DMA-90" when you said "DMC 90"? Assuming the answer is yes, I'm basing the following on the specs shown here
for the amp, and here
for the preamp.
Assuming that the phono stage and line stage gains are set to their maximum positions, with the volume control turned all the way up the total gain of the preamp is 40 + 36 = 76 db. That corresponds to a voltage gain of 6310 times, based on the relation db = 20 times the logarithm of the ratio of two voltages. That will boost the rated nominal output of the cartridge to 0.28 mv x 6310 = 1.77 volts, which is more than the 1.5 volts that is spec'd as being required to drive the amp to full power. And particularly high volume musical peaks will cause the cartridge to put out significantly more than 0.28 mv. Therefore you won't find yourself running out of range on the volume control.
Phono section noise performance is specified as "95 dB A Weighted, ref 100 mV @ 1 KHz." I suspect that the 100 mv level refers to the output of the phono section, rather than the input, but I'm not 100% certain of that. 100 mv is of course way more than the input would ever see from a moving coil or moving magnet phono cartridge, but that doesn't necessarily mean that the noise level is not spec'd based on a hypothetical input of 100 mv.
If, as I suspect, the 100 mv refers to the output of the phono section, since 40 db corresponds to a voltage gain of 100, the A-weighted noise level referenced to the input would be 95 db below 1 mv, which is 84 db below 0.28 mv. That represents exceptionally good performance, and would almost certainly assure acceptably low hiss levels.
In the event that the 100 mv refers to the input of the phono section (which I doubt), it would imply an A-weighted noise level of 95 - 40 = 55 db below 1 mv, or 44 db below 0.28 mv, which would most likely be unacceptable. In that case you would probably want to add a moving coil step-up transformer, ahead of the preamp's inputs.