First thing to do is put your hand over the top of the cup with the stalk between your fingers, grab the cup with your other hand and turn it upside down now give it a genital shake downwards so the plant and dirt come out in your hand, have a look and see how the roots are doing, if it's full time to re-pot, if still room to grow put back in and follow instruction below. You will not damage your plant this way and next time use the translucent cups not the red one and you can see whats happening and when they are watered right. Always water twice or wait for all the water to be absorbed and water again, trust me on this when you have the translucent cups you will understand. And no the light won't bother the roots.
If you packed the soil down when you planted them than it's compacted. If you just poured it in and evened it out your all good, If you think it's compacted use a fork and starting at the edge break up the first 1 to 2 inches around the cup stay away from the plant and only go about 1 inch in, do when dry.
