Yes, you will be requested to leave when you are caught taking photos and they will record down your documents and see your pictures if they see you taking photos in the interchange. But I think it is not a big problem for foreigners, who can act foolish and get away with it.
Maybe you can try like this:
From hotel:
147 to Clementi Interchange (B9)
154 to Boon Lay (Super Olympian/Olympian Hotdog/B10M Hotdog)
Industrial/Tuas buses to Boon Lay (Volvo Hotdog)
MRT to Jurong East
51 to hotel (Trident, but not easy)
It's easier to get Tridents at Hougang Central.