There is no real way to stop the darkening of cherry, just the nature of the beast. You can slow down the process by keeping your work out of direct sunlight.
Cherry is prone to blotching. The darkening or clouding up of the softer tissues in the wood when a stain/finish is applied. A quality blotch control, pre-conditioner is strongly suggested prior to any staining/finishing. Charles Neil makes the product I use. Easy to apply with great results. It works as advertised. Not sure what you may have available where your at.
https://www.youtube.com/watch?v=IfCYMdrP8rM
Do a youtube search on "blotch control" to learn more about it. Something well worth learning about.
I"m not a big fan of staining unless it is necessary. I like to let the natural beauty of the wood speak for itself. If you do stain, experiment on several pieces of the same wood you are using to get a real feel for what the end result will be.
While you may be diligent about avoiding water marks, the potential exists. As well as dings and scratches. For a table or desk top at a minimum I'd suggest a good Laquer schedule topcoat. Easy to apply, easy to maintain and repair if necessary. A polyurethane is much more durable and an excellent choice for high traffic items. A bit more difficult to touch up but provides excellent protection. Both of these can be brought up to a high gloss finish if desired. A little more work/time but man, well worth the effort!
A de-waxed shellac is another option you might consider. Easy to apply, maximizes transparency when using blonde or platinum blonde shellacs.
Before deciding on what course you want to take, EXPERIMENT first.