Need to know exactly what the point in the machine is.
Because you may not really require an i9 if your tasks are not up to it, unless you really just want one.
But correct me if i am wrong, your asking if you should exchange your current i3 to a 65W TDP or 95W TDP.
I am assuming you run an i3 9400 variant as it has a 65W TDP.
Now we need to know if the machine is a prebuilt like DrMrLordX states, or its something you built.
I am leaning on it being something you built but you not knowing the board maker has me a bit worried.
Look inside the case, the board maker or board name should be spam'd somewhere on the board very visable.
If its not, then that is not a good sign as its a prebuilt. All if not most aftermarket boards these days are very flashy, and will have the maker or board name spam'd in clear view for "gamer" aesthetics.
Reason why we ask this is because of how the power delivery setups are from something like Dell vs an aftermarket like ASUS.
Dell's make there boards exact to spec, so throwing a 95W chip on a 65W board unless the board was designed to run 95W will be a fast way to kill the board. (Tiny Prebuilts for example)
If its an aftermarket board, i see no problem in you throwing whatever cpu you want in that system as long as its a 9th gen.
Also if your board does not support overclocking, there is no point at all in you getting a "K" cpu.