What are you going for? Are the dark areas even close to what you want? You can stain over the lighter areas making them darker. You can sand the lightest areas (front edge) with a coarser grit, such as 120 instead of 150, so the wood will accept more stain. Here is a SITE with fixes for common problems.

I sampled the colors of your paint, your flooring, and the bench. All have an orange tone, so should work together, if you can get the stain color evened out. A gel stain can be applied over other stains if you want to change the tone, perhaps make it more gray. However, staining is like dying fabric in that the original color affects the outcome. If you dye a blue shirt red it will end up purple.

Your floors are pretty light in color. If you want the top of the bench to have that light appearance, which I think would look great with the dark gray framing around it, you might not need any stain at all. This is assuming you will be using another finish on the wood -- polyurethane or oil finish, etc. It's hard to know how much sanding would be necessary to get rid of the overly stained dark areas. Hopefully you have a machine for this!

On the other hand, if you don't want to bother will more sanding, you could make a cushion to exactly cover the bench top and forget the bad stain experience. It looks like the front edge didn't soak up the stain so much, so that might be just fine.

Some people use a "grain filler" kind of product before staining a porous wood to keep the stain from soaking in some areas more than others.