Does alcohol interact badly with prescription adderal xl?

Not advised. Adderall (dextroamphetamine and racemic amphetamine) is a stimulant used to treat adhd. Alcohol is a depressant. Taking stimulants and depressants together is rarely a good idea as they tend to pull your body in two different directions. If you are drinking alcohol while under a doctor's care for adhd, you need to make sure they are aware of this so that they can make the best decisions for your care and treatment.
It can. Depends on how much you drink. If you have adhd, alcohol is not going to make you better focussed or smarter, and should be avoided in excess. Safe drinking limits in men your age are no more than 2 standard drinks per day, and no more than 4 on any occasion, and no more than 14 drinks per week. In those amounts, it is not likely to cause problems, but if you drink regularly, talk to your doctor.