Long story short, I tore my ACL in high school and it hasn't been right since. I've had knee problems off/on for years. Some days, I'm fine and can do just about anything. Other times, all I can do is walk or maybe use the recumbent cycle. My knee has its good and bad days.
Even though your ACL injury is from 1.5 years ago, your knee is still extremely weak and probably unstable. You need to avoid any high impact types of exercises. So jumping jacks or plyometric exercises are out. running is out too. You should stick to low impact exercises and strength training.
You can do the 30 Day Shred, but you may want to march in place whenever they do jumping jacks or hopping/jumping.
Do you have a bike ? Cycling is low impact and should be easier on your knee. Swimming is another great cardiovascular option. I've been cycling for years and my knees are fine. My knees are not fine when they do high impact stuff. I can feel it.