It's a proposal that's been touted for years. Another article states that there would have to be consultation with parents before any changes to CBBC's broadcasting hours were made. Plus, where are they going to magic the DTT bandwidth from this time?
I'm guessing it will be BBC 4 which loses the two hours of air time, with BBC 3 sharing spectrum with CBeebies instead, especially as BBC 4 is also having it's budget reduced slightly.
A while ago I did wonder if come DSO, BBC Three would get its own stream on Freeview (and become a 24 hour channel), and CBBC on another stream would run until around 9pm, with something else in its place e.g. Community 9pm to 7am. Evening programming (6pm to 9pm) would then be for the teen/pre-teen kids.
Now BBC only has one Freeview SD mux that won't be possible. With the current set-up (CBBC and BBC Three sharing a stream), extending CBBC to 9pm would mean BBC Three being unable to start until 9pm. I think there's more need for BBC Three to start at 7pm than BBC Four, e.g. BBC Three shows the ESC Semi-finals 8pm to 10pm each May, and it also does Glastonbury Festival coverage. Therefore most likely, they could re-arrange the streams as follows:
CBBC / BBC Four timeshare - CBBC 7am to 9pm; BBC Four 9pm to 7am
CBeebies / BBC Three timeshare - CBeebies 6am to 7pm; BBC Three 7pm to 6am
BBC Three currently shuts about 4am and shows a caption it loses the stream to CBBC, which then transmits half hour's worth of a rolling trailer. Likewise BBC Four broadcasts a caption from around 4am until it loses the stream to CBeebies around 5:30am, which itself broadcasts a rolling trailer until 6am.
Under the suggested stream arrangement, CBBC and CBeebies could ditch those pre-opening trailers. That way, BBC Three could show
programmes
(not a caption) until 5:58am when CBeebies takes over the stream, and immediately shows its first programme of the day e.g. Tikkabilla, and BBC Four could show programmes until 6:58am when CBBC takes over the stream and immediately shows its first programme of the day.