Problem using op_checksequenceverify (op_csv) with relative time flag
i manage to find answer for myself.

OP_CSV date consensus is based on median time past (mtp), not block's confirmed date.

once funding tx above has been confirmed, it is located in block#1609592 with block MTP is 2019-11-24 09:05:26 (UTC 0). At same time, chain's MTP is 2019-11-24 09:25:27 (UTC 0)

now come to spending tx, since utxo's confirmed date i used is 2019-11-24 09:05:26, plus 512 seconds = 2019-11-24 09:13:58. Therefore i can spend immediately as chain's MTP is more than 2019-11-24 09:13:58.