I agree with everything RBG has advised. Do not put it in the outer pot as is and drilling holes in ceramic is problematic, at least I have not had much luck. It's time to move it up into a larger pot, and here is where you have some research to do and some decisions to make.
Begin to research proper bonsai soils and why we use them [url=https://www.helpfulgardener.com/forum/viewtopic.php?t=3422]here.[/url] Make sure to follow the links as well. If you are satisfied with the image that your tree currently presents you can purchase an appropriately sized bonsai pot and a small bag of soil on-line and re-pot now. Summer is a good time to re-pot Ficus as they will respond well now. You can even get inexpensive plastic bonsai pots that look OK.
If, on the other hand, you would like to grow it our more you don't really need a bonsai pot at all. Any nursery pot of an appropriate size can be used. The idea behind all this is that bonsai are developed
in either nursery containers or other, usually shallow and broad, containers for years in order to attain a mature appearance. They are only placed in bonsai pots for appearance sake when they really deserve it. A lot of 'bonsai' sold at mass retailers are really just young cuttings in fancy pots. That's fine if that's what you desire but there is so much more to bonsai.
This is the choice you need to make now, accept it for what it is or approach it with more of an eye to the future. look [url=https://www.helpfulgardener.com/forum/viewtopic.php?t=27007]here[/url] to see an example of a mature Ficus that a member has recently acquired. Give the above some thought and we will be glad to assist you further.
A few other thoughts, the type of moss on your tree is not really growing and is really just top-dressing and think I would remove it. Doing so will give you a better idea of the condition of the soil and when to water.
The plastic pot sits on top of a piece of Styrofoam so that the excess water has a place to pool.
It would really be better to remove the inner pot before you water the tree and only return it after the excess water has drained. Never allow the inner pot to remain in standing water.