Without having access to the schematic, it looks like the ICs are getting the right power, although I would have expected pin 7 of the CD4013 to reference 0V (ground). Usually, squealing means something is floating (not connected) and turning something into an oscillator. In this build, it could also be that the suboscillator is shorting or leaking into the audio path, or the oscillator is not being controlled properly.
I've marked up the photo of the rear of your veroboard (and rotated it to match the flipped layout). There is one lead that looks to not be soldered completely, so I would reflow that. There is also a lot of damage to the vero traces, either from a being rubbed off mechanically or dissolved off chemically. Did you use an abrasive or corrosive chemical to clean the board? I didn't highlight all of the potentially disconnected traces, so your best bet is going to be to run solder across each connected trace to ensure they are connected.
You can avoid these issues in the future by inspecting the board before cutting as some cheaper veroboards may come with damaged traces. I usually have to sort through lots of the cheaper boards to find ones that look the best and just bin the rest. You also may want to adjust your soldering iron temperature, it looks like some joints are lumpy & cold, which can be the result of low iron temperatures & a dirty tip. My advice for anybody is to clean & tin when you pick the iron up, and clean & tin again before you put it down. That will ensure you've removed the old solder oxide layer (which doesn't flow onto your board) and extend the life of your tip a LOT.