Can I use this 950° soldering iron on electronics?
It's inappropriate for electronics. 

That said, if you have a deft touch it's possible to use such an iron without destroying the copper-laminate adhesive, but I would not recommend it. For example if you tried to desolder something the board would quickly be ruined- pads lifted.  

You could reduce the power to half by wiring a 1N4007 in series with the mains, but a better choice would be to buy a soldering iron or solder station that has closed-loop control of the tip temperature, preferably adjustable. The 25W iron you mention would not have this feature. Try to pick something with replacement tips you can get locally (or at least readily) in various sizes and types.