Well - they make "clear-colored" wood stains, but I've never used any.
You can paint over wood stains, but sand it well first.
I would use polyurethane and HD latex paint.
I'm not sure about the most efficient way, or necessarily the best looking, but I made one recently, and it looked great. Here's what I did.
Or better yet, what I would do to make your table:
This is the picture of the court that I went by.
I taped off the parts of the table that I wanted to keep the "wood grain" look. I placed some plastic on the table, and used FROG TAPE to seal the edges. You have Sandeply, so it shouldn't be a huge deal if you just use painters tape, but I would use Frog Tape just to make sure. It helps to seal the tape, so the paint won't seep under the tape and make ugly lines. I've had some serious problems with this on some cornhole boards I made.
Don't worry about taping the center court line or 3 point lines, but be sure to measure and leave the "blue lanes" on Duke's court uncovered.
Once done, prime the whole thing white. Use two coats.
Then get some thick paper, and type out the endzone lettering. I'm sure you can look around for a good matching font online. Print the lettering off. Put down Frog Tape along each endzone, covering the entire endzone. Create a stencil using the printed lettering, and put it on the endzone. Take a razor blade and carefully cue the lettering outlines into the tape. Then peel the excess off - leaving the lettering in tape in the endzone.
Then Frog tape a small border around the endzone, that will essentially be the white line that separate the wood grain from the blue endzones.
Then paint blue where it needs to be, using 3 to 4 coats.
The hardest part is next - the three point lines. I found a marking kit at a local craft shop that was for circles and semicircles, and it works great. i would recommend looking for on, and painting these lines by hand. Dont forget the center-court line.
I bought a sticker of the exact Duke logo and just put it in the center of the table. I found this easier than painting.
Next, get some fine grained sandpaper and lightly, but efficiently, sand the entire table. Sand the thickly painted endzones and lanes thoroughly, so the clear coat will stick well to the latex paint.
The final step, and probably the one question you want to hear the answer to, is use a clear polyurethane coat. I bought an extra clear color at Home Dept, and it works great. Especially where I used several coats. I would definitely use several coats to ensure protection and a smooth surface, but lightly sand between each coat.
The several coats of polyurethane also makes the sticker logo in the middle look more realistic.
If you are still unsure, get some stain samples and polyurethane samples from your local hardware store and test on the reverse side.
Hope this helps.