Using instruments and dance as a way to praise God is not unbiblical, and I bet that they would use verses to support that as defense for what they are doing
This is one thing that I fear when it comes to Christians who rely on feelings alone for faith. I strongly believe that we can be guided by our feelings by the holy spirit, but satan masquerades as an angel of light to deceive us, and I 100% believe he can use this same thing people come to rely on over Gods word in order to lead people astray.
Im sure every single adult in that audience would tell you they are being guided by the holy spirit.