As others have said, it is definitely OK to use this calculator for AQA, and a quick glance over the other specifications indicate that it should be OK for them too - including WJEC.
I often find that some teachers think calculators like this are not allowed when they are. It is a great timesaver to check the values of definite integrals, because if they agree with your value, you don't have to waste time checking them. Similarly for other things which you need to show working for, but you can check if you are right, like simultaneous equations and roots of quadtatics and cubics.