Not sure how old your LO is, but if you've all woken for the day at 9am I would just feed at WU, do a normal length A time and then nap when it's due, ie just start the EAS pattern from WU time. That may mean you just do two naps today to keep a normal BT, or you may have to wake from last nap. Either way I'd assume the lie-in was needed to catch up on lost sleep, do EAS the best you can today and aim for normal BT, then start again tomorrow.