Define “safe”. You’re young, so shutting down your natural test production for something you can achieve naturally on your own, is a risk and a silly one in my opinion. You run the risk of infertility issues, low testosterone issues. Most people do recover, however there are plenty of stories of young kids struggling to recover. Why take that risk when you can put on muscle without it?
Get the notion of BF% out of your head, it’s a pointless number, seriously. I remember I was the same way at your age, however I personally feel like I look better now between 12-15% than I did at 7/8%. That’s all personal preference, however staying under 11% AND rapidly gaining muscle might not be easy. What’s the harm in eating a bit surplus, gaining a good amount of muscle, then leaning out to your desired look?
Numbers are silly, and body fat percentages seem to almost never be accurate. I used to swear by dexascans, however my last few of me questioning that. It seems as though bod pods are the only truly accurate form. So you’ll be chasing a number that is subjective to say the least.