worth applying for A*AA course if i'm predicted AAAB?

The best thing you can you is drop the subject you got predicted a 'B' in and increase your effort in one of the subjects you were predicted an A to get an A star. There's nothing at all to be gained from having 3As and 1B.

the thing is that the B was for my easiest subject (business) and i feel like i can easily get that up to an A*, although it's not a required subject for any of the degrees i just doubt my abilities in getting an A* for my other subjects. but ty for the advice!

Taking 4 subjects is pointless and risks spreading your time to thinly resulting in you missing grades. There is absolutely nothing to gain from trying to be clever and taking 4 subjects. A*AA will always be looked on better by universities than AAAB. Drop one and try to achieve the grades required.
As far as whether you will get offers nobody knows. The more competitive the course and university the less likely they are to accept a dropped grade. This is why it is advisable to apply to universities with a range of required grades. Risking 1 or maybe 2 wont be a problem if you have others at or below the grades. If the 2 reject you then you will still have offers. Trying for all 5 is extremely risky and foolish.